Category: Chemistry

Introduction

Radiation refers to the phenomenon when energy in the form of waves or particles is emitted. This can include alpha particles, beta particles, and even gamma photons. Alpha particles are also referred to as alpha radiation or alpha waves, and they consist of two protons and two neutrons.

What is an Alpha particle?

Alpha particles are produced through the α-decay of certain radioactive elements such as uranium, thorium, radium, and plutonium. They are positively charged and are denoted by the symbol . It is interesting to note that these particles are quite similar to helium nuclei and may even be referred to as doubly ionised helium atom \(H{e^{2 + }}\).

Since these particles carry a double positive charge, they have high ionizing power but do not penetrate too much into matter. When α-decay occurs, the parent element emits an alpha particle, causing it to transform into a different element. For example, uranium-238 undergoes α-decay by emitting α-particles and is transformed into thorium-234.

Since the alpha particle carries two protons and two neutrons, the atomic and amss numbers of the parent are reduced by 2 and 4, respectively.

Mass Of An Alpha Particle

The mass of an alpha particle is the same as that of a Helium atom, and is given as:

Characteristics of Alpha Particles

Fundamental Properties of Alpha Particles

• Their velocities can range from \(1.4 \times {10^7}\;to\;1.7 \times {10^7}m{s^{ – 1}}\)

• They tend not to deviate from a straight line path
• They are highly ionising, typically 100 times as ionising as beta particles and \({10^4}\) times as ionising as gamma rays. They can even ionise biomolecules.
• They have low penetration depth and may even be blocked by a sheet of paper.
• Typically, the penetration power is 1/1000 times that of beta rays and 1/100000 times that of gamma rays.
• They can interact with matter via coulomb forces.
• Alpha particles lose kinetic energy quickly and thus, have short range.
• Due to the charge on them, they are easily deflected by electric and magnetic fields. The positive charge makes them attracted to the negative plates.
• They can produce both fluorescence and phosphorescence.
• These particles can be scattered by heavy elements like gold.
• Alpha particles can cause heating effects and though they can affect photographic plates, the effect is very weak.
• Their mass is roughly four times that of Hydrogen atoms.

Uses of Alpha Radiation

•  Ra-226 has been used to destroy cancerous cells. Due to their low penetration depth, they only affect the malignant cells and leave normal cells unharmed.
• Americium – 241 is an alpha source that is used in smoke detectors. Smoke ionizes it, which causes an electric current, causing the trigger of an alarm.
• Satellites and spacecraft use Plutonium – 238 in their batteries. The heat produced due to alpha decay is converted into other forms of energy.
• Medical pacemakers used to utilize Plutonium – 238 as fuel source but this practice has non  been discontinued.
•  Polonium – 21, an alpha emitter, is used to reduce static in industrial settings. Being positively charged, the alpha particles attract the electrons and reduce chances of static electricity.
• Strontium – 90 is an alpha emitter that is used as a fuel source for oceanic buoys by the U.S coast guards. 

Summary

Alpha particles consist of two protons and two neutrons bound together, which is equivalent to a helium nucleus. They have high ionization power, allowing them to ionize matter easily. 

In nature, alpha particles are emitted from radioactive elements such as U-238 and R-226, and they can also be produced artificially in reactors using radioisotopes like plutonium and californium. These particles have various applications, including cancer treatment, smoke detectors, pacemakers, and thermoelectric generators. The relatively low penetration depth of these particles means that they cannot penetrate the skin and thus, are not harmful.

Frequently Asked Questions

1. How can we detect alpha particles detected?

The following methods can be used to detect charged particles:

• Ionization chamber
• Scintillation counter
• Semiconductor detector

2. How do alpha particles interact with matter?

Alpha particles can interact with matter via coulombic forces. Due to their high ionization power, they can also lose energy by knocking an electron out of the atom they collide with.

3. Discuss the ionization and penetration power of alpha, beta, and gamma rays.

Alpha particles have a high ionization power, which is  times greater than beta rays and  times greater than gamma rays. However, their relatively higher mass lends them a low penetrating power, which is 1/1000 of beta rays and 1/100000 of gamma rays. But these particles can ionize biomolecules.

4. Is there a difference between alpha decay and alpha particle?

Yes. Alpha decay is the process by which, an unstable nucleus emits an alpha particle and a daughter nucleus. Alpha particles are the particles emitted in this process and are equivalent to doubly positively charged Helium atom.

5. Are alpha particles dangerous? How can we protect ourselves?

Alpha particles have high ionisation power, but their penetration depth is relatively low, which means they cannot penetrate the outer layer of our skin and thus, aren’t that harmful. 

However, if you inhale or ingest an alpha source, it can affect your organs internally, which may prove dangerous. The alpha radiation can reach your lungs, which may cause cancer. When consumed through water, it can affect the kidneys. Further, high levels of exposure to alpha radiation can lead to DNA damage, and even larger exposure can cause Acute Radiation Syndrome.

Protection from alpha radiation

Protection from alpha radiation is simple and may be achieved as follows:

1. Either decrease time of exposure or,
2. Move away from radiation source or,
3. Use a shield. 

Introduction

It is possible for elements in nature to change into another by various processes. Such processes are classified as nuclear reactions. For instance, nuclear decay is a type of reaction which occurs when an unstable nucleus emits energy, nucleons, and/or atoms to achieve stability. Various other types of reactions also exist.  

Various types of nuclear decay can occur in nature and one of those is alpha decay. This process occurs when a nucleus emits an alpha particle to gain stability. It might be worth mentioning that an alpha particle is very much like a Helium atom with a charge of +2e, i.e., two protons and two neutrons.  

Alpha Decay

Since alpha decay involves the emission of nucleons, parent nucleus, which is the nucleus undergoing alpha decay, is changed. Its atomic and mass numbers decrease by 2 and 4, respectively. Simultaneously, energy is also released in the form of electromagnetic radiation, which is why the process is termed radioactive. 

Alpha Decay Equation 

It is possible to represent nuclear reactions via equations. The general equation of alpha decay is as follows: 

Here, 

• X is the parent nucleus which undergoes alpha decay. 
• Y is the daughter nucleus which the parent is converted into. 
• α is the alpha particle that is emitted as a byproduct, along with energy. 

Understanding Q Value of Alpha Decay 

To understand the energy involved in a nuclear reaction and whether it is possible for the reaction to take place, Q value can be used. It is the difference in kinetic energies of initial and final nuclei and for alpha decay, we find it as follows: take the difference in the masses of the initial elements and the final products of the reaction, and multiply by \({c^2}\). That is, 

Here: 

• Q is the Q value of the reaction. 
• mi is the mass of the initial nucleus. 
• \({m_f}\) is the mass of the final nucleus. 

• \({m_α}\)  is alpha particle mass. 
• c represents the vacuum velocity of light. 

It should be noted that units are important while working with such equations. The above equation is for the case where masses are given in units of MeV/\({c^2}\). 

As previously mentioned, Q value can help us understand whether a reaction is possible. Not all elements can undergo all types of reactions. For example, whether alpha decay is possible depends on the Q value described above. Alpha decay is accompanied by a release of energy, which happens when the Q value is negative. 

On the other hand, a very stable parent nucleus will have greater mass than that of the final products, making the Q value positive. This would correspond to energy input instead of output, making alpha decay in such a case, unfavourable. Thus, Q value can help us understand whether a reaction is possible or not.

What are the Major Components of the Equation that Represents Alpha Decay? 

The alpha decay equation is as follows: 

Its major components are summarized below: 

• X represents the original or parent nucleus. Usually, this is an unstable element and it is observed that most elements undergoing alpha decay have mass numbers greater than 200. 
• Y is the nucleus obtained after the reaction is complete. It has lower mass and atomic numbers than the parent and as represented, these numbers decrease by 4 and 2, respectively. It is generally more stable. 
• α is the alpha particle. In simple words, alpha particles are just nuclei of Helium atom. 

Alpha Decay Example 

1. Decay of Radium-226 

The decay of Radium-226 is a common example. Ra-226 is a very stable isotope with half-life of 1600 years but it can undergo alpha decay to generate Radon gas. The process also releases ionizing radiation. 

The equation representing this decay is as follows: 

2. Decay of Uranium-238 

The decay of Uranium 238 into Thorium is one of the most commonly cited alpha decay examples. Take a look: 

What happens in Alpha Decay? 

We mentioned that the process of alpha decay is radioactive. That is, energy in the form of radiation is released. Further, alpha decay causes an unstable nucleus to change into a more stable one. This parent nucleus is generally heavy and when alpha decay occurs, it releases an alpha particle, which reduces its mass and makes it more stable. The alpha particle is ejected and travels a certain distance before becoming inert. 

Helium nucleus emission

Gamow Theory of Alpha Decay 

The energy of the alpha particle emitted can help us better understand the reaction. There are a large number of ways to measure this energy and a theoretical approach is to use Gamow’s theory, which connects the half-life of the process with the energy of the alpha particle. The foundation of this theory is in quantum mechanics and thus, its derivation is slightly complex. 

The theory assumes the daughter nucleus and the alpha particle to be present inside the parent before the reaction occurs. Since nuclear potential is immensely strong, classical mechanics forbids these nuclei from escaping. However, quantum mechanically, the concept of “tunnelling” allows for a small probability of escape for these particles. 

The relation derived from this hypothesis is the same as the one empirically derived by Geiger and Nuttal. It is summarized below: 

• λ is the decay constant. 
• Z is the atomic number of the parent. 
• E is the total kinetic energy of the daughter and the alpha particle. 
• \({a_1}\) and \({a_2}\) are constants.  

Summary

It is possible for certain elements in nature to be transformed into other elements via processes known as nuclear reactions. One common example of such reactions is nuclear decay, where an unstable nucleus decays into a more stable one by releasing energy and nucleons. Alpha decay is also a type of nuclear/radioactive decay, which occurs when an unstbale parent nucleus decays into a stabler one. In this process, an alpha particle is released, which is a Helium atom carrying a charge of +2e. The equation of alpha decay is given below:

In alpha decay, mass and atomic numbers reduce by 4 and 2, respectively.

Gamow’s theory of alpha decay relates half-life of parent with the energy of alpha particle and uses quantum mechanical calculations to arrive at the result. It posits that the products of the reaction are present in the parent already and the decay occurs by quantum mechanical tunnelling.

 

Frequently Asked Questions

1. Are alpha particles dangerous?

Alpha particles can not penetrate the human skin too much and thus, are comparatively safe. But since our eyes are sensitive, alpha particles can damage the cornea. Further, if an alpha particle source enters the body, it can damage organs from inside.

2. How far do alpha particles penetrate into matter?

Alpha particles easily absorbed even by a thin sheet of paper and they become inert after a few cm of travelling in air.

3. What is the typical kinetic energy of an alpha particle?

Alpha particles travel are heavy and thus, travel at around 5 MeV. This is equivalent to a velocity of 15,000 km/s.

4. What other types of nuclear decay are observed?

Alpha, beta, and gamma decay are three common nuclear decays of which, gamma decay is the most dangerous one. It emits high energy photons that can penetrate human skin and cause cancer.

5. What are the uses of alpha decay processes?

Americium-241 is an alpha particle source that is used in smoke detectors. The process is also used in artificial pacemakers for generating power. Other medical applications include Radium-223 for the treatment of bone cancer. 

Introduction

All of our energy is generated by fundamental chemical and physical processes. Throughout history, this has typically been accomplished by burning carbon-based resources such as wood, coal, and gas, or by utilising the energy of the sun, wind, and water. Through two physical processes known as fusion and fission, atoms can generate vast amounts of energy. They generate millions of times more energy than traditional sources through nuclear processes.

The history of nuclear fusion began at the turn of the 20th century with research into how stars generated their own energy. As potential applications increased to include warfare, energy generation, and rocket propulsion, the field’s emphasis broadened to include a comprehensive examination into the nature of matter and energy. In the 1930s, scientists, led by Hans Bethe, determined that nuclear fusion was the sun’s energy source and that it was both theoretically and practically practicable.

The term “fission” is used to describe the splitting of a heavy nucleus into two roughly equal-sized lighter nuclei. The revelation that such an unusual nuclear reaction could occur marked the conclusion of a really spectacular event in the history of science, and it ushered in an era of intense and fruitful research.

What is Nuclear Fission?

Fission refers to the fragmentation of anything into smaller pieces. In this sense, nuclear fission refers to the splitting or fragmentation of a large atom into two or more smaller atoms. These little atoms are technically light in weight. Breakdown of the nuclear fission process releases large amounts of energy, proving that it is an exothermic process. The uranium fission process is described below.

Nuclear Fission Reaction

What is Nuclear Fusion?

The word “fuse” means joining two or more other objects. The process by which two or more atoms come together to form a bigger atom is known as nuclear fusion. Because the act of fusing two atoms needs consuming energy, nuclear fusion is endothermic. 

The Distinction between Nuclear Fission and Nuclear Fusion in Tabular form:

Nuclear Fission vs Nuclear Fusion

What are Nuclear Fission and Nuclear Fusion in Physics?

The two basic natural forces that bind atoms together are weak and strong nuclear bonds. The total amount of energy held in atomic bonds is referred to as the binding energy. The greater the amount of binding energy stored inside the bonds, the more stable the atom. Atoms make additional efforts to promote stability by increasing their binding energy.

Nuclear Fusion versus Nuclear Fission

The differences between nuclear fusion and nuclear fission are given below :

Use of Nuclear Fission and Nuclear Fusion

 Both nuclear fission and fusion have many potential uses. Use of nuclear fission in power generation is significant.

•  Thermal energy for nuclear power plants is generated through nuclear fission. This heat is then used to turn water into steam, which is then used to power electrical generators. 
• About 21.5% of the electricity in the US comes from nuclear power plants. Nuclear fission employing uranium-235, which is also used in photographic sources, produces cesium-137 (Cs-137) and other rare radioisotopes. Nuclear fission energy can be used to power submarines and even some types of surface watercraft. Radioactive isotopes created from nuclear fission are employed in many types of medical imaging and cancer treatment.
• This is a perfect example of how nuclear fusion can be put to good use. After combining at the sun’s core, hydrogen nuclei release a tremendous amount of heat, which we feel as helium’s presence on Earth. Fusion might potentially become the primary commercial electricity generation method. 
• There are several potential applications for the energy produced by fusion reactions, including but not limited to: space heating, industrial processes, fissile fuel for fission reactors, and synthetic fuel.

Summary

An atom is split into two parts by a process known as nuclear fission, which is done to produce energy. The splitting of the uranium-235 nucleus when it is bombarded with neutrons is an important example of nuclear fission. On the other hand, it happens when two atoms combine and release energy. The name for this energy-producing process is nuclear fusion. This is how the Sun and other stars emit energy.

 

Frequently Asked Questions:

1. Apart from uranium, which other element is commonly used as fuel in fission reactors?

Ans: Thorium outnumbers uranium in the natural world. It can only be used as a fuel when combined with a fissile substance, like reprocessed plutonium, because it is fertile rather than fissile on its own. Fissile uranium-233 can be produced using thorium fuels and employed in a variety of nuclear reactor designs.

2. What is the moderator used in nuclear reactor?

Ans: To mitigate the dangers of fast-moving neutrons, a moderator is inserted into the nuclear reactor core. Forcing a nuclear chain reaction is much simplified by the inclusion of a moderator.

3. What particle is used to trigger the fission of a uranium nucleus?

Ans: Fission happens when a neutron collides with an atom, causing it to become excited and divide into two smaller atoms (called fission products). Moreover, extra neutrons are released, which can set off a chain reaction. Each atomic fission results in the release of vast amounts of energy.

Introduction

By treating an aryl hydrazone of a ketone/aldehyde with an acid or a variety of metal & dehydrated metal salt catalysts, \(N{H_3}\) may be removed, leading to the creation of an indole. This process is known as the Fischer indole synthesis. By directly putting an equal molar combination of aryl hydrazine as well as aldehyde/ketone into indolization settings, the actual separation of the aryl hydrazone is frequently avoided. Like this, the reduction of the appropriate aryldiazonium salt/ N-nitroso arylalkylamine in the vicinity of the CO compound results in the in-situ formation of the aryl hydrazine, which then immediately results in the aryl hydrazone. By treating pyruvic acid 1-methyl phenylhydrazone by HCl in 1883, Fischer & Jourdan achieved the very 1st indolization of an aryl hydrazone.

What is meant by Fischer Indole Synthesis?

It is one of the most effective and time-tested techniques for creating indoles. Fischer obtained the very 1st patent for it in 1883. In the introduction of acids, aryl hydrazine, as well as substituted ketone/aldehyde, can be used to create a variety of indoles. Under acidic circumstances, a phenylhydrazine, as well as a ketone/aldehyde, undergoes a chemical reaction to produce the heterocyclic aromatic indole.

The obvious benefit of this method is the usage of a wide variety of alcohols as opposed to their oxidized equivalents. The process may be completed in a single pot and offers moderate to good yields for the indoles while tolerating replacement on both hydrazines as well as alcohol. The parameters of idolization are frequently used without first isolating the aryl hydrazine using an equimolar combination of ketone/aldehyde. The same is true for aryl hydrazone, which may be immediately exposed to indolization settings in the vicinity of carbonyl without first isolating the aryl hydrazone. This is done by reducing the linked aryl diazonium /N-nitroso arylalkylamine salt.

The Fischer Indole Synthesis’s Main Features include:

1. Since the aryl hydrazones don’t have to be separated, the indole synthesis may be done in a single pot.
2. Unsymmetrical ketones generate 2 region-isomeric 2,3-disubstituted indoles exhibiting region-selectivity based on intermediate acidity, the substitution of hydrazine, as well as steric effects.
3. 1,2-diketones can be used to produce mono- as well as bis-indoles, having mono-indoles often being formed in refluxing alcohols with powerful acid catalysts.

Fischer Indole Synthesis Mechanism

Steps:

1. The product of aryl hydrazine and ketone is aryl hydrazone.
2. Protonation occurs at more basic N.
3. The proton is lost creating a pi bond neutralizing N to yield ene- hydrazone.
4. Again, protonation at the same N and undergo [3-3] sigmatropic shift generating a C-C bond at the ortho position of the benzene ring.
5. Isomerization takes place making a more stable aniline form and restoring the aromaticity of the ring.
6. N from aniline moiety attacks iminium ions intramolecular fashion to secure 5 membered rings.
7. One proton is lost, and acid catalyzes and by elimination of \(N{H_3}\), the final product, indole is formed.

Fischer Indolization

Fischer Indole Reaction is a convergent method that has been established to have an indole ring system that exists in many bioactive compounds. The method uses an irregular Fischer indolization sequence to condense hydrazines containing latent aldehydes. This eventually produces goods that include Indoline. The approach is convergent, gentle, simple to apply, all-encompassing, and may be applied to obtain enantioenriched products.

There has been the 1st catalytic Fischer asymmetric Indolization. When a spirocyclic chiral \({H_3}P{O_4}\) is present at a loading of 5 mol percent, it is highly enantioselective. Effective catalyst turnover has been accomplished by including a mildly acidic cation exchange resin that eliminates the ammonia produced. Different genera of three -substituted tetrahydro carbazoles are produced by the reaction, which may be carried out under favourable circumstances.

The discontinuous Fischer indolization is a powerful method for generating fused indole ring structures, which are present in several natural alkaloids. A brief description of the whole synthesis of communes is provided in alkaloids as well as perophoramidine. The method is focused on the usage of the disrupted Fischer indolization to produce the tetracyclic indole in natural products.

Fischer Indole Synthesis Procedure

Aryl hydrazine reacts with a ketone/aldehyde to produce an aryl hydrazone that isomerizes to the appropriate enzyme. A cyclic [3,3]-sigmatropic rearrangement results in the production of an imine following protonation. Under acid catalysis, the resultant imine forms a cyclic amino acetal, which removes \(N{H_3}\) to produce indole. Indole is a heterocyclic compound that is very important to biological systems. The redox-active indole side chain of tryptophan is one of the primary charge carriers engaged in the transfer of electrons in proteins. Tryptophan is one of the most important intrinsic fluorophores in the investigation of protein fluorescence due to the indole’s optical characteristics. Reductive deamination of tryptophan results in the intermediary molecule indole pyruvic acid, which is then converted into indole. The end products of the process are pyruvate, indole, ammonium, as well as water.

Summary

It can be concluded that under acidic circumstances, a phenylhydrazine, as well as a ketone/aldehyde, undergoes a reaction known as Fischer Indole Synthesis that results in the heterocyclic aromatic indole. Emil Fischer discovered the reaction in 1883. Today, this process is frequently used to create triptan-class antimigraine medications. Aryl hydrazine reacts with a ketone/aldehyde to produce an aryl hydrazone that isomerizes to the appropriate enzyme. A cyclic [3,3]-sigmatropic rearrangement results in the production of an imine following protonation. Under acid catalysis, the resultant imine forms a cyclic amino acetal, which removes \(N{H_3}\) to produce the energetically advantageous aromatic compound indole.

 

Frequently Asked Questions

1. Is indole basic or acidic?

Ans. Indole is a weak base, just like pyrrole. It interacts with KOH and Grignard reagents as well as polymerization by strong acids.

2. What is the Indole test?

Ans. Indole Test: This test shows that certain bacteria can break down the medium-accumulating amino acid tryptophan into indole. The test for indole synthesis is crucial for identifying Enterobacteriaceae.

3. What causes the electrophilic substitution reaction in indole?

Ans. The 3rd carbon in the indole ring is the most reactive site. This is even more reactive than benzene in terms of the electrophilic substitution process.

4. The indole ring is present in which amino acid?

Ans. L-tryptophan is the only protein amino acid (AA) with an indole ring, and when it undergoes biotransformation in living things, it either helps to preserve this chemical group in cells as well as tissues or breaks it down by producing a range of bioactive chemicals in both circumstances.

5. What reagent is utilized in the indole test?

Ans. Directly into the tube, add 5 drops of the Kovács reagent to check for the formation of indole. In a short time of introducing the reagent to the media, the reagent layer on top of the medium develops a pink to cherry-red ring, which signifies a positive indole test.

Introduction

A chemical is produced when primary alcohol is reacting with a carboxylic acid in the presence of sulphuric acid. The odour of this chemical is fruity and pleasant. The resulting chemical is known as ester. The chemical reaction that results in the creation of the ester is called an esterification reaction. There are three distinct pathways that lead to esterification,  by reacting acid anhydride with alcohol, by Chloroform and Alcohol or by acetic acid and ethanol. 

What is Meant by the Fischer Esterification Mechanism?

Producing an ester from a carboxylic acid and an alcohol in the presence of a strong acid catalyst is known as the Fischer Esterification Mechanism. Fischer esterification, named for its co-inventors Arthur Speir and Emil Fischer, is also commonly referred to as Fischer-Speier esterification. Alcohol and heat are required for the reaction to take occur. In 1895, they first described the Fischer Esterification process. In most cases, Fischer esterification can be reversed. Common catalysts for the Fischer Esterification Mechanism include sulphuric acid, p-toluene sulfonic acid (PTSA), and Lewis acids like  \({C_3}{F_9}{O_9}{S_3}Sc\) (Scandium triflate). The most stable ester appears to become the predominate product due to its latency, suggesting that this is essentially a thermodynamically regulated mechanism. This may be an essential feature when there are multiple reaction hotspots and unwanted byproduct esters to avoid. On the other hand, kinetic controls are commonly employed in reactions involving acid anhydrides and acid chlorides, which proceed quickly.

The Mechanism of Fischer Esterification

In the existence of abundant alcohol as well as a strong acid catalyst, this process transforms carboxylic acids to such an ester as the end product, including water as a residue. There are several stages in the mechanism-

1. The acid catalyst acts as a nucleophile of the carbonyl oxygen, allowing it to undergo a nucleophilic assault from ethanol initially.
2. The alcohol initiates a nucleophilic attack on the carbonyl. A solitary pair of electrons from the O atom of its alcohol bonds with carbonyl carbon, destroying its π bond with another O atom. The electrons in the bond go upwards to the O, neutralizing their positive electrical charge. It then generates an oxonium ion.
3. Following that, a proton exchange from the oxonium ion to the OH group occurs, culminating in quite an active site. It might be divided into 2 stages: firstly, the alcohol deprotonates that oxonium ion, producing the ternary complex, as well as subsequently the OH group adopts the alcohol’s proton.
4. Just after 1,2 removal of water, the protonated ester has been produced. A solitary O atom builds a π bond involving the carbon, liberating the water.
5. The leftover positively charged O has been deprotonated to produce the necessary ester.

Esterification Mechanism

Advantages of the Fischer Esterification Mechanism

Fischer esterification’s simplicity is one of its primary advantages over more traditional esterification processes. A simple acidic environment can be employed if acid-sensitive functional groups are never a worry; acidic medium could be used; softer acids should be included at the expense of prolonged reaction times.

However, the “direct” nature of the chemicals means that they have had a surprisingly small worldwide impact in terms of garbage and reagent toxicity.

Greenhouse gases or ozone depleters are two of the many environmental hazards that alkyl halides could pose.

The reaction of acid chlorides with atmospheric moisture produces hydrochloric acid gas and they appear to be extremely toxic, but they also react rapidly with water and other nucleophiles; they have been freely quenched from other nucleophiles apart from the preferred alcohol; and even its most popular formulation paths take into account the release of hazardous CO or \(S{O_2}\) gases.

Disadvantages of the Fischer Esterification Mechanism

Fisher esterification techniques have the limitations of being thermodynamically reversible and typically having sluggish reaction rates, which can range from many weeks to years depending on the reaction conditions. When other functional groups appear to be reactive to strong acid, alternatives may be problematic, and new catalytic acids may be selected.

If the generated ester has a lower boiling point than water and the reagents, it can be evaporated in its place. This is a common occurrence, as esters with no protic functional groups have a lower boiling point than their protic parental reactants. The reaction rate is slowed due to the restriction of the overall reaction temperature, but purification and extraction are simplified if the ester product can be purified independently from the reagents. Then, an excess of the starting material is typically required, and the reaction mixture is sealed before being gently heated.

Examples of the Fischer Esterification Mechanism

Summary

Indeed, Fischer esterification is a chemical process that changes carboxylic acid into an ester. There is a high concentration of alcohol and an active acid catalyst. Through the course of the reaction, there appears to be an even distribution of products and reactants. The formation of an acyl-enzyme intermediate is the initial step in the Fischer Esterification Mechanism. The ester bond is formed when the alcohol reacts with this intermediate. Ultimately, the ester product is hydrolyzed, releasing the enzyme. An ester has been formed within the presence of water, and this reversible process can only be prevented by continuously eliminating the ester. Fischer esterification’s inability to maintain equilibrium has been one of its drawbacks up to now. However, sulphuric acid is perhaps the most common and efficient acid catalyst throughout the esterification procedure. There should be equal proportions of carboxylic acid and sulfuric acid.

Frequently Asked Questions:

1. What is the role of the deprotonation in Fischer Esterification? 

Ans: The deprotonation of the alkoxide ion is necessary for the formation of the ester. It makes the nucleophile strong and favours the reaction kinetically. 

2. What drying agent is used in esterification?

Ans:. Concentrated sulphuric acid is the common dehydrating agent used for preparing esters. A carboxylic acid reacts with an alcohol in the presence of conc. sulphuric acid to form an ester. This process is known as esterification.

3. Why is HCl not used in esterification?

Esterifications are not water sensitive, because water is the reaction product. However, for this same reason, the concentration of the water in the reaction mixture affects the equilibrium point. Thus, it is completely unreasonable to use hydrochloric acid as a catalyst for preparative reactions.

Introduction

The rate of reactions is a word used to describe the rate at which a reaction occurs. The concentration of the reactants is a reliable indicator of the reaction rate. One can think of the rate of a reaction as being directly proportional to the production of the product and inversely proportional to the decreasing concentration of the reactant. The pace of reactions can be calculated with relative ease by tracking the shift in concentration.

For example, the combustion reaction on cellulose occurs rapidly, typically in a matter of seconds, and the rusting of iron is a relatively sluggish process that requires a long time to develop.

What is the Order of Reaction?

The Order of Reaction describes the correlation between process rate and species concentration in a chemical reaction. First, the rate expression (or rate equation) of the reaction must be determined in order to determine its order.

So, the order of a reaction is the exponents to which the reactant species are raised and it depends on the rate of that particular reaction. The order is achieved from the rate law. For example, in a reaction,

aA+bB⟶P

The rate equation is given as:

\(rate = k{[A]^x}{[B]^y}\)

The order of the reactant A is x fand for the reactant B, the order from the equation is y, Thus the overall order of the reaction,, n=x+y . 

Characteristics

• The sequencing of a reaction has certain defining features. There is no guarantee that the response order will always be a whole number. It is clear from the equations themselves that the amount of a reactant used to make a product is crucial. However, this feature is not always present. As a result, the amount of reactant present in a reaction is irrelevant to the outcome of the reaction in some cases. The order of reactions has so certain defining features depending on this. In the case of a zero-order reaction, in which the rate of a reaction is independent of the concentrations of the chemical species involved in the reaction, the order of the reaction is zero.
• Important information to keep in mind is that the reactant concentration may slow down the reaction as well. That is, the concentration of the reactant has a negative relationship to the reaction rate. The order would therefore take on a negative value in that scenario.
• Furthermore, the order of reaction can take a positive value, with the rate being proportional to the concentration. When the amount of a reactant rises, the pace of the reaction quickens.
• In addition, the rate of a reaction is not always a positive or negative integer; in some circumstances, it may be a non-integer value. Quite a few complex reactions involve situations where the values involved are not integers. 

How to Find Order of Reaction?

For every chemical reaction, the idea of the rate of reaction is very important. The order of reaction deals with the idea that how a reactant will influence the rate of a particular reaction. And by the knowledge of the order of reaction, we can focus more on the reactant that will be going to affect the rate of the chemical reaction. So, it is will not be obtained by simply looking into the chemical equation. It requires another method for finding the order of the reaction.

Following Methods Can be Used for Determination of Order of Reaction –

The order of reactions can be easily obtained by the following methods. 

• From the rate equation: By using the rate equation of chemical reactions we can find out the order of the reaction. For example, the order of the following rate is, \(Rate = K{[A]^2}\) , and the order is two.
• By doubling reactants: Doubling the concentration of reactants present chemical equations and observing its effect can help to find out the order of reactions. The experimental method is always used for the determination of order.
• Differential method: The method is also called the initial rate method. As it involves the determination of the rate of reaction by altering one of the reactant concentrations while the rest of the reactant is kept constant. 
• Graphical method: In this method, the chemical reaction that involves only one reactant is determined method. If A is the reactant involved, a graph is plotted in which logA vs time provides a straight line, it will be a first-order reaction. While the graph 1/A vs time is a straight line it will be second order.
• Integral method: The use of an integral form of rate law is used the determination the order of the reaction. 

Difference Between Molecularity and Order of Reaction 

Molecularity and order of reaction are two important terms that deal with chemical reactions. The difference between these two is tabulated below.

Zero Order Reaction 

Zeroth order or Zero-order reactions are chemical reactions that don’t rely on the concentration of chemical species involved in the reaction. The exponents of the reactant in the rate equation are zero.

\(Rate = K{[reactant]^0} = K\)

An example of a reaction that involves a zero-order reaction is the decomposition of N2OThe reaction is,

First Order Reaction 

The rate of reaction which counts on only one of the reactants is a first-order reaction. For such a reaction if the concentration of reactant is doubled the rate of the reaction will also get doubled. 

The rate equation for such reaction is,

rate=k[A]

Hydrolysis of cisplatin, the drug used for the treatment of cancer is an example of a first-order reaction.

Second Order Reaction 

The reaction in which the rate relies on the square of the concentration of reactant is a second-order reaction. For reactions,

2 A → products

The rate equation for the reaction will be,

\(Rate = K{[A]^2}\)

An example of such a reaction is the decomposition of Nitrogen dioxide,

\(2{\rm{ }}N{O_2} \to {\rm{ }}2{\rm{ }}NO{\rm{ }} + {O_2}\)

Pseudo First Order Reaction 

Even though they occur at the second order, their behaviour is more like to that of the first. Such chemical reactions have a pace that is proportional to the product of two reactants, but the appearance of the third reactant cannot be predicted because its concentration will fluctuate so wildly. As a pseudo-first-order reaction, the hydrolysis of ethyl acetate provides a good illustration.

Summary

There is a correlation between the rates of chemical reactions and their respective orders of reaction. Understanding rates is crucial for the development of chemical processes. When calculating the order of a chemical reaction, the exponents included in the concentration data are added together. The reaction order has a unique property in that it can take on negative, non-integer, and positive values.

Reactions are categorised as zero order, first order, second order, pseudo-order, etc., depending on the sequence in which they occur. There are a number of strategies that can be used to establish the reaction’s order. Similarity order of reaction also includes the concept of molecularity, which is commonly used to describe chemical processes. However, these two concepts are not the same at all.

Frequently Asked Questions

1. How does temperature affect the rate of a chemical reaction?

Ans: The reaction rates increase with temperature. Arrhenius Equation is an empirical connection that models the fluctuation of the rate constant with temperature, revealing chemical reaction rates at different temperatures.

2. How is half-life used in radioactive dating?

Ans: Scientists use specialized equipment to measure the amount of an unstable isotope in a sample and the amount of the isotope that it becomes after the isotope decays.

3. Does molecular size affect reaction rate?

Ans: The larger and more complex the reactant molecules, the less chance there is of a collision at the reactive site. Does larger the molecular size of the reactant, lower will be the rate of reaction. 

Introduction

The symbol for an element is a single letter or two-letter abbreviation of the element’s full name. These symbols are helpful when writing out lengthy chemical equations that need the usage of shortened forms of complexes and elements. The number of electrons (\({e^ – }\)) and protons (\({p^ – }\)) in an atom can be determined from its atomic number (Z). In chemistry, an element is defined as a pure substance made up entirely of atoms having the same number of protons in their atomic nuclei.

What are the First 20 Elements of the Periodic Table?

here is the list of 20 elements with symbols and Atomic Number 

Atomic number	Symbol	Element
20	Ca	Calcium
19	K	Potassium
18	Ar	Argon
17	Cl	Chlorine
16	S	Sulfur
15	P	Phosphorus
14	Si	Silicon
13	Al	Aluminum
12	Mg	Magnesium
11	Na	Sodium
10	Ne	Neon
9	F	Fluorine
8	O	Oxygen
7	N	Nitrogen
6	C	Carbon
5	B	Boron
4	Be	Beryllium
3	Li	Lithium
2	He	Helium
1	H	Hydrogen

Master the Periodic Table! Learn about all 118 elements, their symbols, and atomic numbers in our easy-to-understand article. Click here to start exploring now!

Importance of the Atomic Number of An Element in a Periodic Table

The number of protons in the nucleus or the number of electrons (\({e^ – }\)) in a neutral atom is equal to the atomic number. It determines the element’s position in the periodic table.

Eight is the atomic number of oxygen. This means that in the ground state of the nucleus, there are eight protons. There are eight electrons (\({e^ – }\)) in all. NaCl, with an atomic number of 11, also possesses 11 protons in its nucleus. There are 11 electrons in orbit around the nucleus.

 Since the number of electrons in an atom is also its atomic number, the electrical configuration of an atom may be easily predicted using just the atomic number. Because the atomic numbers in the contemporary periodic table increase, this is a very important fact. One final factor that is crucial in determining the properties of an element is its atomic number. The nature of chemical bonds is determined by the number of valence electrons (\({e^ – }\)). 

The periodic table’s atomic number is significant due to following reasons: 

1. If we order elements according to their atomic mass, we also need to list their isotopes, which makes the periodic table too long. However, if we arrange the periodic table according to the atomic number, we don’t need to write the isotopes.
2. If the periodic table were ordered by atomic mass, the element hydrogen (H), which has three isotopes, would occupy three separate spots.
3. The electrical configuration or valence electrons of an atom can be determined by its location in the periodic table, which is in turn determined by its atomic number.
4. The organisation of the elements according to their atomic numbers is simple to learn and copy.
5. If we know the atomic size based on the atomic number, we can use that information to make educated guesses about other properties of the element, such as its ionisation energy, electron affinity, and electronegativity. 
6. Atomic numbers allow us to determine an element’s oxidation state and valency by referencing its electronic configuration.
7. Metals (+ve charge elements) can be distinguished from nonmetals via their oxidation states (-ve charge elements).

How are the First 20 Elements of the Periodic Table Useful for us

The first 20 elements of the periodic table are important to us because they are the basis of all known forms of life. We can’t survive without these things in our bodies. Proteins, nucleic acid, and other building blocks are made from them. The first 20 elements of the periodic table are the most abundant elements on the planet. Some of the most important elements are:

1. Oxygen– It is required for respiration. The energy-producing mechanism that governs the metabolisms of most life forms is respiration. Humans, like many living beings, need oxygen to breathe.  It is produced during photosynthesis in plants as well as various microorganisms.
2. Carbon– It accounts for 18% of the body. It can be found in protein, sugar, & and other vital substances such as glucose. It can also be found in fossil fuels such as petroleum, CNG, & others.
3. Aluminium– Because it is malleable as well as soft, aluminium is utilised to select items such as utensils, aeroplane parts, window frames, & so on.
4. Silicon is a semiconductor that is utilised in computer chips.
5. Phosphorus– In the armed services, phosphorus is utilised to build weapons.  It is a crucial component of ATP, the body’s energy currency.
6. Calcium -It aids in bone strength maintenance. 

Noble Gases in the First 20 Elements of the Periodic Table

The noble gases are a set of six non-reactive gases found at the far right of the periodic table. They are located in the final group of the periodic table, Group 18. They lack aroma, colour, combustibility, and reactivity and have no discernible flavour. These subatomic particles can glow and carry an electric current. One organic chemist called these elements “lazy” because they don’t react with anything. Some examples of noble gases are radon, helium, xenon, krypton, neon, and argon. 

Summary

There are a total of 118 atoms in the periodic table. The first twenty elements of the periodic table is the first step towards mastering all of the elements. An element is a substance that can neither be oxidised nor reduced chemically. The elements’ atomic numbers follow the order in which they appear on the periodic table. We value the first 20 elements of the periodic table because they form the building blocks of all known life.

Without these in our systems, we just won’t make it. They are used as precursors in the synthesis of proteins, nucleic acid, and other biomolecules.

Frequently Asked Questions

1. What is the difference between a s-block element and a p-block element? 

Ans: S-block elements are elements in the s-block of the periodic table, while p-block elements are elements in the p-block of the periodic table.

2. Are all the first elements of the periodic table non metals?

Ans: No, all the first elements of the periodic table are not non metals. Hydrogen and the p block elements are non metals while the s block elements are metals. 

3. Are noble gases abundant in nature? 

Ans: Every one of the noble gases exists in the atmosphere. Argon makes up 0.934% of the air we breathe, whereas the other 18 elements are present in extremely minute quantities. The radioactive decay of (\({potassium^ 40 }\)) is the primary source of atmospheric argon. In the atmosphere, neon makes up 0.0018 percent, helium 0.00052%, krypton 0.00011%, and xenon 0.000009%.

4. What is the periodic table, and why is it important?

Ans: The periodic table is a chart that organizes chemical elements by their atomic number, electron configurations, and recurring chemical properties. It is important because it allows scientists to predict the properties of elements and their compounds, making it an essential tool in the study of chemistry and the development of new materials.

Introduction

Under the right circumstances, fire can be a very helpful chemical reaction. It’s useful in a lot of situations, but it can be dangerous if it’s burned improperly. The portable gadget known as a fire extinguisher is used to put out fires of any size. People depend on fire for a wide variety of tasks. Fire is essential for many industrial processes; without it, it would be impossible to imagine things like cooking and lighting. Dry vegetation in woods has caught fire before, posing a threat to wildlife for miles around. Multiple types of fire extinguishers are used to put out the various blazes. Many various kinds of fire extinguishers are available, including those that use water and foam, carbon dioxide, dry chemicals, wet chemicals, water mist, and so on.

What is a Fire Extinguisher? 

To put out a fire, you need an extinguisher, which can contain dry carbon, water, or a chemical. It’s put to use dousing flames caused by things like cooking oil, flammable gases, petroleum, wood, clothing, paint, and so on. These are stashed in convenient, easy-to-reach locations. Classifications of fire depend on the nature of the combustible substance.

Fire Extinguisher

Explain the Principle on which a Fire Extinguisher works 

A fire extinguisher relies on the “fire triangle,” a set of interrelated concepts for its operation.

• When fighting a fire, the primary rule is to extinguish it at its origin.
• The availability of oxygen is the second essential item.
• The third component is the fuel being used in the fire.

Fire Triangle

Types of fire extinguisher

The fire extinguisher is of numerous varieties, since the fire extinguisher acts according to the source of the fire. There are seven distinct varieties of fire extinguisher, each distinguished by the chemical it contains.

1. Water and foam Based: Electric appliance, coal, paper, textile, wood, etc. fires can all be put out with a foam base fire extinguisher. Use a water-based extinguisher for flames involving metal, wood, cooking grease, and similar materials.
2. Carbon Dioxide Based: In this type of extinguisher contains carbon dioxide, which hinders the supply of oxygen and helps cool down fire. This is used for fires caused by electricity. 
3. Wet Chemical-based Extinguisher: This type of extinguisher is used for the fire caused by oils, fats, and in commercial kitchens. It removes the heat based on the fire triangle principle. 
4. Dry Powder Fire Extinguisher: A dry powder is filled in an extinguisher; it hinders the supply of oxygen to cool down the heat generated. It is used in fire caused by metals, like sodium, zirconium, etc. 
5. Clean Agent Fire Extinguisher: It contains a halogenated clean agent i.e., halogen with ozone-depleting hydrocarbons. 
6. Water Mist Extinguisher: They are used to quench fires caused by wood, paper, as well as electric appliances.
7. Dry Chemical Fire Extinguisher: It is filled with a dry chemical that interrupts the chemical reaction that is the cause of the fires

Working of Water Fire Extinguisher 

• Water extinguishers are filled with water and designed in such a way that when the seal is broken it expels the water in force to quench a fire. 
• First, the seal is broken, and the safety pin is pulled out.
• Then, the lever of the extinguisher is squeezed. 
• By squeezing the lever, it forces a pointed rod within the valve, that punctures the cylinder containing high-pressure gas. 
• The Gas-filled in the cylinder is released into the cylinder filled with water and, forces the water downward.
• Pressured water then came out of the pipe, this pressure triggered water to cool down the fire from 4 to 6 feet away. 

Preparation of Soda Acid Fire Extinguisher with diagram and explain How it works?

The Soda acid fire extinguisher is prepared with sodium bicarbonate and diluted sulphuric acid. Let’s check the process of preparation of a Soda acid fire extinguisher.

• First, we need a wash bottle with a nozzle, we fill that bottle with 20 ml of sodium bicarbonate  \(\left( {NaHC{O_3}} \right)\) solution,
• Then, we suspend an ignition tube by a thread that contains a dilute solution of sulphuric acid \(\left( {{H_2}S{O_4}} \right)\)  in the wash bottle,
• The next step is to close the mouth of the bottle, 
• After closing the bottle, we tilt the bottle in such a way that the acid-filled ignition tube reacts with the sodium bicarbonate solution, 
• After some time, we notice that there is discharge coming out of the nozzle of the bottle.
• That discharge is the of carbon dioxide \(C{O_2}\) , and other products are sodium sulphates and water.
• When we take the discharge near the fire it quenches the supply of oxygen within the fire and the fire cools down.
• The Carbon dioxide \(C{O_2}\) released during the reaction work as an extinguisher that hinders the supply of oxygen in fire and hence fire cools down.

\({\bf{2NaHC}}{{\bf{O}}_3} + {{\bf{H}}_2}{\bf{S}}{{\bf{O}}_4} \to {\rm{ }}{\bf{N}}{{\bf{a}}_2}{\bf{S}}{{\bf{O}}_4} + {\bf{2}}{{\bf{H}}_2}{\bf{O}} + {\bf{2C}}{{\bf{O}}_2}\)

Preparation of Soda Fire Extinguisher

Summary

In the above tutorial, we have studied the fire extinguisher. A fire extinguisher is a container that contains different types of elements like foam, wet chemical, dry chemical, carbon dioxide, water, water mist, etc. we must choose a correct fire extinguisher when a fire breaks out because a wrong type of extinguisher can ignite the fire more despite cooling it down. The fire is divided into five classes class A, B, C, D, and K. These are divided according to the type of material causing the fire i.e., wood, paper, electric appliance, oil, fat, metals, etc. These types of fires are quenched by different types of fire extinguishers known as Foam, water, chemical, and carbon dioxide-based extinguishers. 

 

Frequently Asked Questions: 

1. What is the difference between a rechargeable and a non-rechargeable fire extinguisher? 

Ans. Rechargeable fire extinguishers can be refilled and reused, while non-rechargeable fire extinguishers must be replaced after use. 

2. How long does a fire extinguisher last? 

Ans. The lifespan of a fire extinguisher depends on the type of extinguisher and the environment in which it is stored. Generally, fire extinguishers should be replaced every 5-10 years.

3. What is the best way to store a fire extinguisher? 

Ans. Fire extinguishers should be stored in a cool, dry place away from direct sunlight and away from any heat sources.

Introduction

Organic reactions discovered by a specific scientist are known as “named reactions,” and the namesake scientist is often credited with the discovery. Many of these reactions  have important practical and economic applications. One such reaction with a name in organic chemistry is the Finkelstein reaction. Hans Finkelstein, a German chemist, first described what is now known as the Finkelstein reaction. Because of its significance, this organic reaction bears the scientist’s name. This. Organic exchange reactions include the swapping of one halogen atom from one chemical for another halogen atom from another.

What is the Finkelstein Reaction? 

Finkelstein reaction follows \(S{N_2}\) mechanism which involves the replacement of halogen atom. The reaction leads to the formation of alkyl iodide by the reaction of alkyl halides with metal halide in the presence of a polar aprotic solvent.  The reaction takes place as follows:

The alkyl halide should be primary. The halogens used for this reaction may be Chlorine or Bromine. The solvent used for the reaction is acetic acid which is a polar aprotic solvent. 

Examples of Finkelstein Reaction 

Many alkyl halides can be made or synthesized with the aid of Finkelstein’s reaction, some examples are:

• The reaction of sodium iodide with methyl bromide results in the formation of methyl iodide is an example of Finkelstein’s reaction. And sodium bromide is obtained as a by-product. The reaction is:

• The reaction of sodium iodide with ethyl chloride results in the formation of ethyl iodide is also an example of Finkelstein’s reaction. And sodium chloride is obtained as an acid by-product. The reaction is,

• The reaction of Sodium iodide with ethyl bromide results in the formation of ethyl iodide is also an example of Finkelstein’s reaction. And sodium bromide is obtained acid by-product. The reaction is,

Finkelstein Reaction Mechanism 

• The reaction process is straightforward and simple to grasp because it follows an SN2 mechanism.
• The stereochemistry of the reactant is flipped at the end of the reaction. 
• The forward reaction is caused by metal halides’ low solubility.
• The alkyl halides are attacked by the nucleophile in the sodium iodide in a single step reaction.
• Which then leads to the production of alkyl iodide and sodium halide.
• The sodium bromide or sodium chloride precipitates out of solution during the process but is miscible with acetone.

Aromatic Finkelstein Reaction 

A catalyst, in addition to the Finkelstein reactants, can increase the efficiency of the Aromatic Finkelstein Reaction.

Aromatic Finkelstein reaction catalysed by copper(I) iodide in the presence of diamine ligands. Tri-n-butyl phosphine and Nickel bromide are two other catalysts that can be used. As shown in the procedure below, Benzyl iodide can be synthesised from benzyl chloride by reacting sodium iodide with acetone.

The oxidative addition reaction is the first stage of the aromatic Finkelstein reaction using a copper catalyst. After that, halide exchanges occur, and finally, reductive elimination takes place, which ultimately leads to the regeneration of an analogous catalyst. An excellent catalyst for the aromatic Finkelstein reaction is Copper (I) Iodide in the presence of a diamine ligand. The following illustration depicts a copper-catalyzed reaction between aromatic halides.

Uses of Finkelstein Reaction 

• This reaction is widely employed for the production of alkyl iodides for application in industry. 
• In addition, it is employed in the analysis of a specific group of alkyl iodides.
• It is through this process that chrysochlamic acid is generated.
• It is a necessary step in the production of -iodoalkyl esters.

Summary 

Finkelstein reaction is an organic named reaction that involves the production of alkyl iodide in a better way. The production of alkyl iodides is a complex mechanism, but it is made easy with the help of this reaction. It involves the use of alkyl halides and metal iodide such as sodium iodide. An organic polar aprotic solvent, acetone is used in the reaction. It is a single step by the molecular reaction which follows the \(S{N_2}\ mechanism. The first step in the reaction is the nucleophilic attack. And then the corresponding replacement of halogens takes place and alkyl iodides will be formed. The sodium salt is also precipitated in the reaction. The reaction also has some other applications, especially in the analysis of alkyl halides. 

Frequently Asked Questions

1. What is the significance of NaI  in Finkelstein’s reaction?

Ans. Sodium iodide has high covalent character than other sodium halides and thus it makes it efficient than other halides as well as other iodine compounds. 

2. What are the limitations of the Finkelstein Reaction? 

Ans: The limitations of the Finkelstein Reaction include the fact that it is not applicable to tertiary alkyl halides, and that it is not applicable to aryl halides.

3. Why is Finkelstein reaction reversible?

Ans. The reaction described by Finkelstein illustrates the exchange of one halogen for another. Since various metal halide salts are soluble in acetone at varying concentrations, halide exchange can occur in both directions.

Introduction

To separate solids from liquids or gases, chemists employ filtration, which often involves using filter paper or a specialised filtration device. You’ll need a filter to let the liquid through but keep the solids out. The liquid that is recovered after filtration is called filtrate. Due to their inability to pass through the filter’s pores, solid substances are a byproduct of the filtration process that can be discarded. Most filtering processes rely on gravity filtration. The porous media used to retain the solids during filtration is called the filter medium, and the filtered suspension is called the slurry.

Filtration Definition

It’s a physical separation technique that can sort compounds out of mixtures, but not the other way around. It’s one of the simplest ways to separate a solid from a liquid that doesn’t dissolve. A filtering media is needed to separate the particulates from the liquids, which are then collected in the beaker. This filter acts as a liquid-only porous medium, stopping solids in their tracks and letting only liquids pass through. Filter cakes are the dense accumulation of solids on a filter after repeated filtration using the same filtering medium.

Filtration Process

The following method is employed when the particles to be separated are smaller than the pores of the filter media. This means the filter media is effective at keeping the liquids out while discouraging the solids. Additionally, the filter cakes act as a secondary filter by preventing the passage of particular slurries.

1. Take water that is to be filtered in a glass beaker.
2. Take a funnel. 
3. Make a little cone out of filter paper & place it on the funnel.
4. Finally, strain the mixture through the filter funnel.
5. The dirt substances will be visible on the filter paper while the remainder of the liquid has been filtered down.

Understanding the Concept of Filtration

Filtration is the process used to remove solid particles from a liquid or gaseous medium. Solid substances are always present in liquids and gases. By definition, a filter is a media that allows a liquid to pass through but traps any solids within it.

Filtration Diagram

The most frequent method of filtering is to use gravity to settle the substances first. The solution is then placed over filter paper, & the water drops because of gravitational attraction, & the residual stays in the filter paper itself.

 Filtration process

Filters in Use

1. Common filtering aids included silica, diatomaceous earth, cellulose, and perlite.
2. They have multiple practical applications, either alone or in tandem with conventional paper filters.
3. Brewing coffee involves passing hot water through a filter and grounds.
4. Coffee fluid is the result of filtration.
5. Tea bags (paper filters) are used similarly to accomplish the soaking process.
6. Organs that function as natural filters include the kidneys.
7. The glomerulus purifies the blood.
8. Many vital chemicals are reabsorbed into the circulatory system.
9. To get rid of allergens like dust and pollen from the air, HEPA filters are used in air conditioners and several types of vacuum cleaners. 
10. To remove contaminants from the water, many aquariums use filters made of fibres.
11. Belt filters are used to remove precious metals during the mining process.
12. Aquifer water is typically safe to drink since it has already been filtered by the earth’s permeable and solid rock.

Applications of Filtration

1. Dust is currently collected using vacuums with attached filters.
2. In rainwater harvesting, water from iss collected and stored underground. Before being used for drinking and cooking, this water is disinfected in a series of sedimentation tanks and filters.
3. Soil, sand, and insects can all be removed from water by filtration.
4. By absorbing the essential oils of flowers, fruits, and nuts, many oils become fragrant and nutrient-dense. They are purified and put to use in the pharmaceutical industry.
5. In the scientific world, filtration plays a crucial role. Some water-based compounds dissolve in oil, whereas those that don’t leave a residue that can be redissolved and used again by adding oil to the mixture.

Seven Steps of the Water Purification Process

Ion Exchange & Coagulation:

This is the initial stage in the procedure. The water from urban areas is polluted with undesired minerals, & this procedure assists in the removal of the minerals that generate hard water. This method is utilized to separate heavy metals such as iron. The dirt substances are subsequently deposited at the tank’s bottom.

Sedimentation:

The water then travels through the sedimentation procedure after the 1st stage. When the water settles, the floc sinks to the bottom. Sediment filters are used to catch dirt particles. This assists in preventing contamination of the equipment.

Filtration & Granular Activated Carbon:

Water is filtered & then transported through layers of sand, charcoal, & other materials in this procedure. The substances left behind from sedimentation are eliminated. Herbicides, chlorine, & other contaminants are eliminated by a carbon filtering process.

Disinfection:

Water is transported into a closed tank with UV lamps that act as a sterilising agent throughout this operation. If it’s underground water, this procedure is sufficient to purify it since all microbes are destroyed. 

Carbon Filters:

Carbon filters are used to adsorb impurities left after disinfection such as coulour impurities. 

Reverse Osmosis:

A semipermeable membrane is employed in this case to remove pollutants from the water. All dissolved contaminants left over from the previous processes are eliminated here. In addition, at this step, a sweet flavour is added to the water.

Store Purified Water:

After the above-mentioned procedure, clean water is kept in tanks.

Summary

The process of filtration is used to separate various liquid mixes. It can’t be used to purify chemicals in any way. The addition of a filtration medium component is required. As filtration velocity increases, the filter cake grows thicker. There is no cloudiness whatsoever in the filtrate. Sedimentation, distillation, evaporation, and decantation are only a few of the filtration techniques available. After completing the filtration process, the filters cannot be reused and must be discarded. While the pollutants being filtered out may be harmful, publicly discarding the filters can pose an even greater threat to the environment and its inhabitants.

Frequently Asked Questions

1. What type of carbon is used in carbon filtering?

Activated carbon is used in carbon filtering which has a size of 0.5 to 50 μm. A bed of this charcoal is used to remove impurities through adsorption. 

2. How is distillation different from filtration?

Distillation uses an external heat source to change the concerned liquid to gaseous phase and isolate the pure liquid. . Filtration uses specific filters to remove the impurities from the concerned liquid. 

3. Which chemical disinfectant is used in water purification?

Chemicals such as bleach, alcohol, phenols, and iodine are used to purify water and kill microorganisms.