Tag: Chemistry

An Introduction to a Separation Technique: Centrifugation

When we look around, there are many objects of various sizes, shapes, and textures. The element that scientists refer to as matter makes up everything in the cosmos. Everything is matter, including the air we breathe, the food we consume, rocks, clouds, stars, plants, animals, and even a single drop of water or sand. These compounds each have a unique nature and set of characteristics. They might be impure, or they might be completely pure. Looking around, we can also see that everything described above has mass and takes up space.

What are Techniques Available to Separate the Mixture

By using everyday physical techniques like hand-picking, sieving, and filtering, heterogeneous mixtures can be broken down into their components. The components of a combination sometimes need to be separated using specialized methods. Several of these methods include:

• Centrifugation
• Evaporation
• Sublimation
• Chromatography
• Fraction Distillation and Distillation

What is the Principle of Centrifugation

Particles with densities greater than the solvent’s density sink, while lighter particles float to the surface. They move faster when there is a greater density differential. Gravity can be replaced by a centrifuge’s much stronger centrifugal force, which can be used to separate different particles in a solution by exploiting even minor changes in density. The centrifuge operates on the sedimentation principle, which states that denser materials and particles flow outward in the radial direction as a result of centripetal acceleration. As they move to the centre, less dense objects are displaced.

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Process of Centrifugation for separating cream from milk

A separator is a centrifugal machine that separates skim milk from the cream. Milk is a liquid that contains tiny oil droplets suspended in it. The milk is centrifuged in a large, closed machine. When the machine is turned on, the milk is spun at an extremely high speed in a container. As a result, the milk is separated into cream and skim milk. Because the cream is lighter, it floats on top of the skimmed milk. It can then be removed. To separate milk and cream, centrifugation is used.

Summary

Centrifugation, which involves rapidly rotating solutions of molecules around an axis in a centrifuge rotor, can be used to separate different-density molecules. One of the most useful and widely used techniques in molecular biology laboratories.

Frequently Asked Questions

1. What are the applications of centrifugation?
Ans. Some applications of centrifugation are-

• Separation of two miscible substances
• Subcellular organelle fractionation
• Separation of chalk powder and water
• Skimmed milk is made by removing the fat from milk.
• Wine clarification and stabilization

2. What are the methods by which heterogeneous mixtures can be separated?
Ans. Heterogeneous mixtures can be broken down into their constituents using common physical techniques such as handpicking, sieving, and filtering. Sometimes the components of a combination must be separated using specialized methods. Among these techniques are:

• Centrifugation
• Evaporation
• Sublimation
• Chromatography
• Fractional and full distillation

3. What do you mean by Mixture?
Ans. More than one type of pure form of matter, also known as substance, makes up a mixture. No physical process can split a substance into different types of matter.

An Introduction to Chromatography

The Greek words chroma, which means “colour,” and graphein, which means “to write,” are the roots of the word “chromatography.” In this procedure, the mixture to be separated is applied to a stationary phase (solid or liquid), and a pure solvent—such as water or any gas—is then allowed to slowly travel across the stationary phase, transporting the components separately based on their solubility in the pure solvent.

Principle of Chromatography

The chromatography principle is that “a mixture is applied to the surface or into a solid, and the fluid stationary phase (stable phase) separates from each other while moving with the help of the mobile phase”.

How to Separate Components from Black Ink

1. A thin strip of filter paper is cut out and a line is drawn 3 cm above the lower end of the filter paper. This is referred to as the reference line.
2. In the centre of the drawn line, a small dot of black ink is placed.
3. When the dot of black ink is dry, it is lowered into the water-filled chromatography jar.
4. The filter paper should be immersed so that the black ink dot is above the water level in the jar.
5. The setup should be left alone for a while.
6. The component of black ink that is more soluble in the water rises faster and higher up on the filter paper as the water begins to rise from the lower end of the filter paper. The level to which water rises is referred to as the waterfront.
7. Some coloured spots are observed corresponding to the separated components of the black ink, depending on the number of components present in the black ink.

Summary

The sample mixture is dissolved as the solvent rises through the paper, and it then travels up the paper. Because of differences in solubility and attraction to paper, smaller particles travel further than larger particles.

Frequently Asked Questions

1. What are the advantages of Chromatography?

Ans. The advantages of chromatography:

1. A very small quantity of the substance can be separated.
2. Components with very similar physical and chemical properties can be separated.
3. It defines the different constituents of a mixture.
4. It also helps in the quantitative estimation of components of a mixture.

2. What do you mean by Heterogeneous solution?

Ans. A heterogeneous mixture can be defined as a solution with a non-uniform composition, such as dye, milk, and sand water solution.  

3. What are the different types of dyes?

Ans. The natural dyes are henna, walnut shells, turmeric, and catechu. Some synthetic dyes are methyl orange, methyl red, congo red, malachite green, rosaniline, pararosaniline, crystal violet, phenolphthalein, indigo, fluorescein, and anthraquinone dye.

Element Symbols in Chemistry: An Overview

Element names were originally derived from popular locations where they were discovered. The same as the copper taken from Cyprus. Furthermore, specific colours inspired some names. Gold, for example, was named after the English word for yellow.

Element symbols and names are currently approved by the International Union of Pure and Applied Chemistry (IUPAC). It is worth noting that many symbols are usually the first one or two letters of their English name. In addition, the first letter of a symbol is always capitalised or uppercase.

Furthermore, the second letter can be lowercase. Examples include hydrogen H, aluminium Al, and cobalt Co. Furthermore, some elements’ symbols are created by combining the first letter of their names with a letter that appears later in their names. Two examples are chlorine and zinc.

There are symbols based on Latin, Greek, or German names for elements. For example, the symbol for iron, Fe, is related to the Latin name Ferrum. This also applies to sodium (Na) natrium and potassium (K) kalium. As a result, each element has a distinct name as well as a chemical symbol.

Symbols of elements derived from the first letter
Nitrogen	N
Sulphur	S
Fluorine	F
Phosphorous	P
Iodine	I
Symbols of elements derived from the first two letters
Barium	Ba
Lithium	Li
Beryllium	Be
Neon	Ne
Silicon	Si
Calcium	Ca
Argon	Ar
Nickel	Ni
Symbols of elements derived from the first and third letters
Arsenic	As
Magnesium	Mg
Chlorine	Cl
Chromium	Cr
Manganese	Mn
Zinc	Zn

The table below provides a few symbols of the elements that are derived from their Latin names:

Element	Latin name	Symbol
Gold	Aurum	Au
Copper	Cuprum	Cu
Mercury	Hydrargyrum	Hg
Tin	Stannum	Sn
Lead	Plumbum	Pb
Antinomy	Stibium	Sb

Summary

The atomic symbols can be used to calculate the number of protons, neutrons, and electrons. Because using the elements’ actual names can be time-consuming, a symbol is useful. Symbols are frequently used to represent chemical reactions. The atomic symbols aid in the identification of the constituent elements of a compound, as well as the element’s grouping and time period.

Frequently Asked Questions

1. What is the meaning of atomic mass?

Ans. The number of particles in an atom of an element is measured by its atomic mass. If the relative abundances of the various isotopes are taken into account, it is an average number.

2. How can molecules be identified from atoms?

Ans. Molecules are made up of two or more atoms, while the atoms themselves are the smallest component of an element.

3. What exactly is a covalent bond?

Ans. The interchange of two electrons across atoms produces a covalent bond, which is a chemical interaction.

An Introduction to Matter

In addition to taking on various forms, the matter is composed of small particles. Because they are so small, it is impossible to see these particles with the human eye. We have mentioned below some of the various properties of matter. There are different states of matter can also be found. The three common states are solids, liquids, and gases. Atoms and other particles with mass and volume are included in the matter.

What do you understand by the Characteristics of Particles of Matter?

We are aware that every substance in our environment is composed of small matter particles. This means that these particles have some attributes and can affect the status of properties. These characteristics of the substance can be either physical or chemical.

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What are the Characteristics of Particles of Matter

The particles of matter are very, very small.

1. The particles of matter have space between them.
2. The particles of matter are constantly moving.
3. The particles of matter attract each other.

Let’s try to explain each characteristic of particles of matter with the help of an experiment.

The particles of matter are very, very small

You can demonstrate the extremely small size of matter particles by carrying out the following experiment with water and potassium permanganate.

1. Put two or three crystals of potassium permanganate in a beaker with 100 ml of water, and mix. The potassium permanganate solution in water will be a dark purple tint.
2. Approximately 10 ml of this solution should be taken out and placed in the second beaker with 90 ml of pure water. The second beaker’s potassium permanganate solution’s colour lightens slightly as a result of this dilution.
3. Take 10 ml of this mixture and add it to the third beaker’s 90 ml of clear water. The solution’s colour will continue to lighten.
4. Continue dilution of the solution in this manner 5–8 times.
5. We obtain a potassium permanganate solution in water in this manner, but the water is still coloured.
6. This experiment demonstrates how a small amount of potassium permanganate crystals may colour a significant amount of water.
7. Therefore, conclude that each potassium permanganate crystal must contain millions of minuscule particles that continually divide into smaller and smaller particles.

The particles of matter have space between them

The experiment below, which uses water and sugar, can be used to demonstrate the gaps between the particles of matter.

1. Have a 100 ml beaker ready.
2. Mark the water level after adding half of the water to the beaker.
3. Utilizing a glass rod, dissolve 50g of sugar.
4. We’ll discover that the sugar solution’s level in the beaker is exactly where the water level was when the beaker was first filled.
5. The crystals of sugar break down into incredibly small particles when they are dissolved in water. Since these sugar particles occupy the spaces between the different water particles, adding sugar to water does not change its volume.
6. When sugar is dissolved in water, there is no change in volume, which indicates that there are voids between the water molecules.

The particles of matter are constantly moving

The investigations on diffusion and Brownian motion gave the particles their characteristic of continual motion. 

1. Water and red ink slowly combine, causing the water to eventually turn crimson. 
2. The movement of matter particles is demonstrated by this action.

The particles of matter attract each other

The forces of attraction that hold matter particles together are known as gravitational forces. Cohesion is the term denoting the force of attraction between particles of the same substance.

1. When a piece of chalk, a cube of ice, and an iron nail are all hit with a hammer, the chalk is very easily broken into smaller pieces while the ice cube requires more energy to break, and the iron nail remains intact even when hit with a lot of force.
2. This demonstrates that the force of attraction between the chalk particles is very weak, the force between the ice particles is a little stronger, and the force between the iron nail particles is quite strong.

Summary

There are three different types of physical nature in the world around us. Solid, liquid, and gas are these we breathe in air, which is a gas, and we drink water, which is a liquid. Because different types of matter contain varied amounts of inter-particle space, we have mentioned three possible states of matter. In this article, we studied the characteristics of solids, liquids, and gases. In a nutshell, this is how matter behaves physically in the universe.

Frequently Asked Questions

Question 1. What are the several forms that matter can take?

Solids, liquids, and gases are the three states in which matter can be found. Ice is a solid, water is a liquid, and steam is water in a gaseous state. Therefore, matter exists in all three states.

Question 2. How can you ascertain the material’s physical characteristics?

We are aware that everything we see is made of something. They take up space and have mass. It’s crucial to realise that not all matter has the same physical characteristics. One common illustration of this fact is the fact that while sand particles are insoluble in water, salt particles are. Therefore, these elements can be referred to as matter’s physical characteristics.

Question 3. What is Diffusion?

In matter, particles are constantly in motion. Diffusion is the term used to describe the natural mixing of particles from two different materials. The diffusion of these particles inside the substance speeds up as the temperature rises. It gets faster because as the temperature rises, the kinetic energy of the particles rises as well. They move quickly as a result.

Introduction

Acids can take lone pairs of electrons from other substances, ions, or molecules. Whereas, Bases are those substances, ions, or molecules that can transfer lone pairs of electrons, whereas based on specific experimental findings, chemical substances were initially categorized as bases and acid substances were initially categorized as bases and acids based on specific experimental outcomes. The Arrhenius concept, the Bronsted-Lowry concept, the solvent system concept, the Lux-flood concept, and the Lewis concept are some of the more well-known contemporary acid-base concepts.

Acid Strength

The ability of an acid to separate into hydrogen ions (\({H^ + }\)) and anions in an aqueous solution are known as its acidic strength. It is represented by the HA chemical formula. The strongest bases are located at the top right of the graph, and the strongest acids are located at the top left. A strong base’s conjugate acid is a weak acid because a strong acid’s conjugate base is weak.

Calculating acid strength with the aid of the equilibrium constant (\({K_a}\)). As a result, chemicals like sulphuric acid \({H_2}S{O_4}\), nitric acid \(HN{O_3}\), and hydrochloric acid HCl are acidic.

\[HA \leftrightarrow {H^ + } + \;{A^ – }\]

For example, 

\[HCl{\rm{ }}\left( {aq} \right){\rm{ }} + {H_2}O\left( l \right) \leftrightarrow {H_3}{O^ + }\left( {aq} \right) + \;C{l^ – }\left( {aq} \right)\]

Here, HCl has a greater tendency to lose a proton and therefore, equilibrium shifts more towards the right.

\({K_a} = \frac{{\Pr oducts}}{{{\mathop{\rm Re}\nolimits} ac\tan ts}} = \frac{{[{H_3}{O^ + }][C{l^ – }]}}{{[HCl][{H_2}O]}}\)

Accordingly, \({K_a}\) is used to describe the strength of only those acids that are weaker than \({H_3}{O^ + }\), and Kb is used to describe the strength of only those bases that are weaker than \(O{H^ – }\). Acidity is represented by the constant \({K_a}\).

The term “\(p{K_a}\) value” is sometimes used to define an element’s acidity. The dissociation constant’s negative logarithm is known as the \(p{K_a}\) value.

\(p{K_a} = {\rm{ }} – log{\rm{ }}{K_a}\,and\,p{K_b} =  – \log {K_b}\)

Strong and Weak Acids

Acids that have a great ability to donate protons are referred to as strong acids. Similar to this, weak acids are those acids, like acetic acid and carbonic acid, that have a high tendency to receive protons. The susceptibility of the base to accept its proton often determines the acid’s strength.

\[{\bf{C}}{{\bf{H}}_{\bf{3}}}{\bf{COOH}}{\rm{ }} + {\bf{N}}{{\bf{H}}_{\bf{3}}} \to {\bf{C}}{{\bf{H}}_{\bf{3}}}{\bf{CO}}{{\bf{O}}^ – } + {\bf{N}}{{\bf{H}}^{{\bf{4}} + }}\]

\[{\bf{C}}{{\bf{H}}_{\bf{3}}}{\bf{COOH}}{\rm{ }} + {{\bf{H}}_{\bf{2}}}{\bf{O}} \to {\bf{C}}{{\bf{H}}_{\bf{3}}}{\bf{CO}}{{\bf{O}}^ – } + {{\bf{H}}_{\bf{3}}}{{\bf{O}}^{ + \;}}\;\]

Acetic acid behaves as a strong acid with ammonia in this reaction, but as a weak acid in water. Hydrochloric acid (HCl), Nitric acid HNO3 and Sulphuric acid H2SO4 are examples of strong acids because they dissociate into ions completely in water.

Acid Strength Determining Factors

The relative conjugate base of acid also affects its strength. On the other hand, the weak conjugate base makes up the strong acid. The weak acid consists of a strong conjugate base.

• Effect of hybridization: Electronegativity and the s-character of the atom both impact how acidic the molecule is. The conjugate base will be more stable the more s-character there are in the hybrid orbitals.
• Periodic trends: The second row of the periodic table shows an increase in acid strength as we move from left to right because the acid gets stronger as the conjugate base gets weaker.
• Resonance effect: When the conjugate base is resonance stabilized, the acid strength rises.
• Inductive effect: The pull of electron density across an atom’s bonds was defined by the indicative effect. The more electronegativity, the stronger the effect; they are exactly proportional to one another.

Order of Acid Strength

The charge density determines an atom’s protons-accepting tendency (or electron pair donation) if there is a significant difference in the size of the atoms that receive the proton. The proton is more strongly drawn to a stronger negative charge.

Comparing the basic strengths of each conjugate base makes it relatively simple to compare the acidity of the bases. The basic strength of halides, for instance, varies as F>Cr> Br>I. This clarifies the order of conjugate acid strength, which is HF <HCL <HBr <HI.

Factors Affecting Acid Strength

The following factors influence an element’s acid strength:

• The polarity of bonds The acid strength of the H-A bond depends on its polarity. The proton tends to leave the molecule more readily when the link is extremely polar, making the molecule a strong acid.
• Bond strength- It is based on how strong the H-A bond is. The energy needed to break a bond decreases with bond strength. As a result, acids are stronger. When comparing the acid strengths of elements belonging to the same group in the periodic table, however, bond strength becomes more significant.

Summary

The information above has given you a thorough understanding of the strength of acid and base. It is found that the basicity or acidity of a chemical is greatly influenced by the inductive effects and charge delocalization. The types of bonds that an ion forms have a significant impact on the acid-base strength of a molecule. The possibility that \({H^ + }\) ions may dissociate increases with the strength of the bonding between protons and anions. In addition, the dissociation of \({H^ + }\) is enhanced by any factor that helps to stabilize the lone pair on the conjugate base.

Frequently Asked Questions

1. What is meant by Dissociation?
Ans: Chemical compounds with ionic connections, such as salts, can be divided into simpler compounds like ions, radicals, or atoms by a process called dissociation.

For example,

\(C{H_3}COOH\) dissociated into ions as:

\[C{H_3}COOH\left( {aq} \right) \leftrightarrow C{H_3}CO{O^ – }\left( {aq} \right){\rm{ }} + {H^ + }\left( {aq} \right)\]

2. Which acid is thought to be the weakest one in the world?
Ans: Those elements that have a low tendency to donate protons due to their high negative charge and which attracts protons more strongly are considered the weakest acid. Hence, hydrogen fluoride (HF) is considered the world’s weakest acid.

3. Even though acetic acid is very soluble in water, why is it characterized as a weak electrolyte?
Ans: The electrolyte’s strength is determined by how ionized it is in solution, not by its concentration. Due to its minimal ionization, acetic acid is a weak acid. It is more soluble because of a hydrogen connection between it and water.

Introduction

Agriculture chemistry is the study of agricultural production, as well as the interaction of plants, bacteria, animals, and their environment. It is a scientific field that studies the composition of both chemistry and biochemistry. We study the production of food, Agri products, and beverages from raw materials in agriculture chemistry. Herbicides, growth regulators, fertilisers, insecticides, and pesticides are examples of agricultural materials. Agricultural chemistry seeks to increase agricultural yield, improve soil quality and fertility, and increase crop yield.

What is Agricultural Chemistry

Agriculture is the process of raising livestock, crops, and other food products. Agriculture in the modern era includes horticulture, agronomy, dairying, soil chemistry, animal husbandry, and so on. Organic, inorganic, and agricultural products are all studied in chemistry. Agricultural chemistry is the application of both agriculture and chemistry that deals with crop production and improvement. Photosynthesis, fertilisers, pesticides and insecticides, irrigation, agricultural produce storage, food processing, chemicals etc.

Why Agricultural Chemistry is important?

Chemistry plays a significant role in crop and livestock production, controlling pathogens, insects, and weeds, and improving crop yield. The world’s population is growing by the day. To meet the growing population’s demand, agricultural chemistry not only improves crop production resources but also uses crops and crop waste to produce renewable fuel and feedstocks. We know that plants produce food through the process of photosynthesis. It is a natural phenomenon, but we can learn about the mechanism involved in the photosynthesis process thanks to agricultural chemistry. This aided us in increasing crop production.

1. Agriculture chemistry contributes to soil quality improvement by testing soil and nutrients.
2. Fertilisers are organic and inorganic compounds that can be found naturally or synthetically. They are applied to the soil during agriculture to increase crop yield. Fertilisers are applied to the soil to provide the macro and micronutrients required for crop production.
3. Pesticides and insecticides are chemicals that are used in crop production to reduce damage caused by insects and pests.
4. Agriculture chemistry aids in the storage of food products, such as sulphur dioxide, which is used to keep grains fresh for long-term storage. Salicylic acid and sodium benzoate are used in food preservation and shelf life extension.
5. Modern agricultural chemistry is now using crop and food waste to produce renewable energy fuels and beverages. Examples include the production of alcohol from bagasse and the use of the Jatropha plant in the production of fuel.

Type of Material	Products
Food	Refined oil, Butter, cheese, etc.
Petroleum	Kerosene, Diesel, Petrol, etc
Construction	Mortar, glass, chemicals, and chemical compounds.
Household	Cooking gas, food process.

What is the purpose of Agricultural Chemistry?

Agricultural Chemistry’s goal is to increase crop production by using pesticides, fungicides, fertilisers, and other chemicals.  In modern chemistry, Crops and other crop wastes are used in the production of biofuels and beverages.

1. As agriculture advances, chemistry improves irrigation techniques through the use of plastic pipes, drip irrigation techniques, sprinkler systems, and so on. Crop production has increased as a result of improved irrigation and a favourable climate.
2. It has invented preservatives such as salicylic acid and sodium benzoates, as well as other chemicals, to extend the shelf life of food products.
3. Agricultural chemistry applied science improves crop quality and yield and lowers production costs.
4. A subfield of agricultural chemistry Chemurgy is working on utilising agricultural products as raw materials for subsequent production such as oil production, petroleum, cooking gas, and so on.

Summary

We learned that agricultural chemistry is a branch of science that deals with the intersection of chemistry and agriculture production. It aids in the production of agricultural products as well as the processing of food and beverages from raw materials. It establishes the relationship between the environment, microbes, plants, and animals. Furthermore, it aids in increasing the quantity and quality of food. Agriculture chemistry incorporates not only chemistry and agriculture, but also microbiology, genetics, physiology, entomology, ecology, and so on.

Frequently Asked Questions

1. Organic fertilisers: what are they?

Ans. Animal manure, fruit and vegetable compost, and fish are examples of living systems from which organic fertilisers are derived. The soil’s microbial population breaks down organic waste. It is rich in potassium, nitrogen, phosphorus, calcium, etc.

2. Inorganic fertilisers: What are they?

Ans. Minerals and synthetic chemicals are used to make inorganic fertiliser, which is synthetic. Petroleum is frequently used to produce inorganic nitrogen.

3. What do you mean by Insecticides and Pesticides?

Ans. Chemicals called pesticides are used to protect crops from things like fungi, weeds, and pests. Chemicals called insecticides are used to eradicate insects that are harmful to crops or livestock. 

Introduction

Most plastic is made up of organic polymers. The chains of carbon atoms that make up these polymers may or may not be linked together with oxygen, sulphur, and nitrogen atoms. Given that they are made up of numerous repeating monomers, plastics can be thought of as both macromolecules and polymers. Different polymers have different backbones and side chains, which is how plastics differ chemically from one another.

What are Plastics?

A wide variety of synthetic and semisynthetic materials are used to create plastics. Different polymers have different backbones and side chains, that is how plastics differ chemically from one another. Polyesters, Silicon, Polyurethanes, Acrylics, and Halogenated are significant groups into which Plastic is divided into various polymers. Different physical characteristics of plastic include its hardness, tensile strength, density, thermal conductivity, and resistance.

What are Thermoplastic Plastics?

1. Thermoplastics are soft and less brittle and are created by additional polymerization. 
2. In organic solvents, they can be dissolved. 
3. The thermoplastics become softer when heated and can therefore be moulded into any shape while still warm. 
4. However, once cooled, the material hardens and rigidifies, holding the moulded shape. Without changing their chemical makeup, they can be repeatedly heated up and moulded into any other shape.

Mention some characteristics of Thermoplastic Plastics

1. Have high molecular mass
2. As the temperature rises, the intermolecular force between the chains weakens, producing a viscous liquid.
3. These polymers are moldable.
4. Easy to recycle
5. These polymers are strong yet lightweight.

What are Thermosetting Plastics?

The macromolecular chains in thermosetting polymers tend to bond with one another to form a cross-linked 3D network. Thermosets are other names for these polymers. The word “thermosetting” is defined as a term that refers to permanently setting upon heating. Thus, after being heated to their pre-thermoset form, the thermosetting polymers acquire their hard texture.

Mention some characteristics of Thermosetting Plastics

1. Typically, thermosetting plastics can withstand heat. They tend to break down before melting, though, when heat is applied at a high intensity.
2. Thermosetting polymers are brittle by nature because heating causes them to lose their elasticity.
3. These polymers cannot be heated again after they have been cured or moulded.
4. The constituent elements used to make the polymer have an impact on the Thermoset density.
5. Typically, thermosets are resistant to chemical harm.

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Advantages of Plastics

1. Plastics are incredibly flexible and can be moulded into a wide variety of designs to suit our needs.
2. It is extremely lightweight and strong in construction.
3. It can be altered into various forms, colours, and textures and gives us a significant marketing advantage.
4. Plastic products are corrosion-resistant and very inexpensive to produce.
5. Instead of other metal materials, plastic products can be handled and stored more easily. They can also be recycled and reused repeatedly.
6. Because plastic is water and moisture-resistant, it is also simple to store and transport food in plastic packets or containers.

Disadvantages of Plastics

1. The biggest issue in the world is how to dispose of plastics because they cannot easily decompose through any natural process, such as the action of bacteria or microbes. Since plastic takes a long time to decompose, it is not environmentally friendly.
2. Plastic contributes to environmental pollution because it releases a lot of harmful fumes into the air when it is burned.
3. Unlike metals, plastics cannot be recycled repeatedly into a wide variety of products because doing so compromises their integrity and quality.
4. Plastics are made from non-renewable resources like petroleum, natural gas, and coal, which contribute to the depletion of these resources and increased dependence on fossil fuels.
5. Plastic production generates significant greenhouse gas emissions, contributing to climate change and its related negative impacts on ecosystems and human societies.
6. Plastics can have adverse effects on human health, with exposure to certain chemicals in plastics linked to various health issues, such as endocrine disruption, cancer, and reproductive problems.
7. The plastic manufacturing process can also negatively impact local communities and ecosystems near production facilities, often releasing toxic chemicals into the air and water, leading to pollution and potential health problems for nearby residents.

Summary

A wide variety of synthetic and semisynthetic materials are used to create plastics. One of the most significant chemical industry products that have an impact on modern life is polymers. The most prevalent examples of polymers are plastics, synthetic fibres, synthetic rubber, etc.  Compared to materials prepared with other metals like iron and copper, plastic-based products are more robust.

Plastic is more effective than metal for the preparation of various materials due to their distinct differences in characteristics. Plastics are incredibly flexible and can be moulded into a huge variety of patterns, vibrant colours, and forms. Consequently, many packaging materials are frequently made of plastic.

Frequently Asked Questions

1. Is plastic employed in the healthcare sector?

Ans. Yes, plastic is useful in the healthcare sector. This is because it is water and temperature-resistant, making it perfect for packaging medications, wound-sealing threads, syringes, gloves, and other medical equipment.

2. Why are plastics naturally non-corrosive?

Ans. The plastics are not corrosive because the materials inside them do not react or go through any chemical reactions. Plastic is used to make a lot of containers, including buckets, mugs, water bottles, and food containers.

3. Why is it necessary to recycle plastic?

Ans. Since almost all types of plastic materials are non-biodegradable and harmful to the environment, recycling plastic is crucial.

Introduction

We currently know about 118 different chemical elements. These elements combine to form numerous compounds. These compounds are classified into Acids, Bases, and Salts based on their chemical properties. “All substances that produce \({H^ + }\) ions when dissolved in water are known as acids, while those that produce \(O{H^ – }\) ions when dissolved in water are known as bases.” When acids and bases are mixed together, they lose their acidic and basic properties, i.e. neutralise, and form salts.

What are Acids

“The word acid comes from the Latin word ‘acidus’ or ‘acere,’ which means sour. The most common feature is their sour taste. In its aqueous solution, an acid produces an ionizable hydronium ion (\({H_3}{O^ + }\)). It causes blue litmus paper to turn red. These dissociate in an aqueous solution to form their constituent ions, as illustrated by the examples below.”

\[HCl{\rm{ }}\left( {aq} \right){\rm{ }} \to {\rm{ }}{H^ + } + {\rm{ }}C{l^ – }\]

\[{H_2}S{O_4}\left( {aq} \right){\rm{ }} \to {\rm{ }}2{H^ + } + {\rm{ }}SO_4^{2 – }\]

\[C{H_3}COOH{\rm{ }}\left( {aq} \right){\rm{ }} \to {\rm{ }}{H^ + } + {\rm{ }}CH3CO{O^ – }\]

What are Bases

Bases are distinguished by their bitter taste and soapy texture. A base is a substance that produces the hydroxyl ion (\(O{H^ – }\)) in an aqueous solution. Bases cause red litmus paper to turn blue.

The bases dissociate in an aqueous solution to form their constituent ions, as shown in the examples below.

\[NaOH{\rm{ }}\left( {aq} \right){\rm{ }} \to {\rm{ }}N{a^ + } + {\rm{ }}O{H^ – }\]

\[Ca{\left( {OH} \right)_2} \to {\rm{ C}}{a^{2 + }} + {\rm{ }}2O{H^ – }\]

What are Salts

When an acidic solution is treated with an alkaline solution or aqueous solution of a metal oxide, a salt is formed, and the solution becomes neutral. A neutralization reaction occurs when \({H^ + }\) ions from an acid combine with \(O{H^ – }\) ions from the base of a metal oxide.

The chemical reactions shown below demonstrate the formation of salt.

\[HCl{\rm{ }} + {\rm{ }}NaOH{\rm{ }} \to {\rm{ }}NaCl{\rm{ }} + {\rm{ }}{H_2}O\]

\[{H_2}S{O_4} + Ca{\left( {OH} \right)_2}\, \to {\rm{ }}CaS{O_4} + {\rm{ }}2{H_2}O\]

Uses of Acids

1. Sulphuric acid is used in the production of fertilizers such as ammonium sulphate, detergents, explosives, plastics, dyes, chemicals, etc.
2. In the textile, food, and leather industries, hydrochloric acid is used as a dye. It is used to remove oxide films from steel objects prior to galvanization.
3. Nitric acid is used in the production of fertilizers like ammonium nitrate, explosives like trinitrotoluene (TNT), plastics, and dye.

Uses of Bases

1. Sodium hydroxide is commonly used in the production of soap, as well as synthetic fibre (Rayon) and paper.
2. The reaction of calcium hydroxide, also known as slaked lime, produces bleaching powder.
3. Magnesium Hydroxide, which acts as an antacid for the body, is used to neutralise excess acid in the stomach and cure indigestion.

Summary

The compounds are classified into Acids, Bases, and Salts based on their chemical properties. “All substances that produce \({H^ + }\) ions when dissolved in water are known as acids, while those that produce \(O{H^ – }\) ions when dissolved in water are known as bases.” When acids and bases are mixed together, they lose their acidic and basic properties, i.e. neutralise, and form salts.

Frequently Asked Questions

1. What are the main differences between a strong acid and a weak acid?

Strong Acids	Weak Acids
When exposed to water, strong acids completely dissociate into their ions.	In an aqueous solution, weak acids are molecules that partially dissociate into ions.
A strong acid solution has a very low pH.	A weak acid solution has a pH of 3-5.
It releases all the H+ ions into the solution.	Partially releases all H+ ions to enter the solution.

2. What are the main differences between a strong base and a weak base?

Strong Bases	Weak Bases
In a solution, a strong base can completely dissociate into its cation and hydroxyl ion.	A weak base partially dissociates into its hydroxyl ion and cation, resulting in an equilibrium state.

3. Do acids conduct electricity?

Ans. The conductivity is due to the presence of ions. Acids dissociate to form (\({H^ + }\)) ions in solutions. Hence, acids conduct electricity.

Introduction

Lemon juice, soap, milk, detergents, and other frequently used items in daily life are all made of acids and bases. In addition to these sustainable acids and bases, a large variety of chemical or mineral acids or bases are also used. Knowing the fundamental characteristics of acids and bases is essential to comprehend the concepts of acids and bases. Water can be combined with acids and bases to produce two different aqueous solutions. Any material that dissolves in water releases free \({H^ + }\) ions to produce hydronium (\({H_3}{O^ + }\)), which is referred to as an acid and releases hydroxyl ions (\(O{H^ – }\)), which is referred to as a base. This acid and base will neutralize each other when combined.

Definition-Acids and Bases

Acids: Chemical substances or compounds that can donate a proton (\({H^ + }\)) or accept electron pairs are known as acids.

Examples include hydrochloric acid (HCl) and sulphuric acid (\({H_2}S{O_4}\)).

Bases are substances or ions that can take a proton or donate a pair of electrons.

Examples include potassium hydroxide (KOH) and sodium hydroxide (NaOH).

Theories of Acids and Bases

Arrhenius theory

1. According to Arrhenius, an acid is any chemical that increases the concentration of protons (\({H^ + }\)) in a solution. For Example, the (\({H^ + }\)) and (\(C{l^ – }\)) ions are created when the acid HCl (which is a base) dissolves in water.

2. Bases are compounds that increase the number of hydroxide ions (\(O{H^ – }\)) in solutions. Take NaOH as an example, which dissolves in water to produce the ions \(N{a^ + }\) and \(O{H^ – }\). Consequently, increasing the \(O{H^ – }\) ion concentration.

Brønsted Lowry theory

This theory states that bases are proton (\({H^ + }\)) acceptors and form a conjugate acid, whereas acids are proton (\({H^ + }\)) donors and form conjugate bases.

For example, hydrochloric acid (HCl), which is a Brønsted-Lowry acid, gives its proton to water when it is mixed with a base (\({H_2}O\)). Water is referred to be the Brønsted-Lowry base when it receives a proton.

Acids and bases in conjugates 

A conjugate base has one more negative (-) charge and one less H-atom than the acid that generated it, whereas a conjugate acid has one more positive (+) charge and one more H-atom than the base that formed it.

As an illustration, in this reaction, a base (\(N{H_3}\)) and an acid (HCl) combine to generate a conjugate acid (\(N{H^{4 + }}\)) and a conjugate base (\(C{l^ – }\)).

Lewis Concept of Acids and Bases

Lewis bases or acids are terms used to describe substances that take electron pairs, whereas Lewis bases or acids are terms used to describe substances that contribute to electron pairs. Thus, the acceptance or donation of electrons determines the acidity or basicity of a substance. 

Acids and bases pH values

The word pH, which stands for potential hydrogen, helps scientists evaluate whether a solution is acidic or basic based on how many hydrogen ions are present in it. It is essentially a pH scale or negative logarithmic scale that ranges from 0 to 14 and quantifies the molar concentration of hydrogen ions from 1 to 14. It has no units for measurement.

The equation for calculating pH is pH =-log [\({H^ + }\)]

When a substance’s pH value is below 7, it is referred to be an acid. If the substance’s pH is more than 7, it is regarded as a base. The substance is regarded as neutral when the pH is 7.

Properties of Acids and Bases

S. No	Property	Acids	Bases
1.	Taste	Sour in taste.	Bitter in taste.
2.	Test with phenolphthalein	Acid turns phenolphthalein colourless.	Basic turns phenolphthalein pink.
3.	Test with litmus paper	Blue litmus turns red.	Red litmus turns blue.
4.	Whenever metals react	Acids and metals react to produce salt and H2 gas. (Only with metals in the activity series above hydrogen.)	Salts and H2 gas are also produced when bases interact with metals (apart from Al).
5.	When carbonates are reacted	Such reactions produce carbon dioxide.	There is no reaction.

Uses of acids

• Hydrochloric acid is used to remove rust from metals
• Acetic acid is diluted into vinegar, which is used in many household processes. Its main application for it is as a food preservative.
• Lemon juice and orange juice both include citric acid as primary ingredients. Additionally, it can be used to preserve food.
• Nitric acid is used in fertilisers, plastic, photographic films, explosives, and dyes.

Uses of bases

• The antidote for food poisoning, bleaching powder, and building construction all employ calcium hydroxide.
• Petroleum is refined using sodium hydroxide, and it is also used to make soap, textiles, and paper.
• Laxatives frequently contain magnesium hydroxide, popularly known as milk of magnesia. It is also used as an antacid, since it lowers any excess acidity in the human stomach.

Summary

Numerous items that are edible and non-toxic, such as grapes, oranges, turmeric powder, milk, and other items, are regarded as bases and acids. Taste and touch are two simple ways to recognise these natural acids and bases. However, some acids and bases are dangerous chemical reagents that cannot be distinguished by their physical qualities; for this reason, their chemical properties are crucial. These acids and bases mostly depend on the \({H^ + }\) ion and \(O{H^ – }\) ion concentrations. Acids are substances that cause protons (\({H^ + }\)) to be produced in water. Bases, on the other hand, are chemicals that generate more hydroxyl ions (\(O{H^ – }\)) in solution. The pH scale can be used to determine the numerical value of acids and bases.

Frequently Asked Questions

1. Are acids electrically conductive?

Ans. The flow of ions’ is what causes the conductivity. Acids split apart in solutions to produce (\({H^ + }\)) ions. Acids, therefore, carry electricity.

2. Why does dilute hydrochloric acid turn blue litmus red, but dry hydrogen chloride gas does not?

Ans. Dry hydrochloric acid does not produce ions, whereas diluted HCl does. Increasing the concentration of \({H^ + }\) in a solution causes it to change from blue litmus to red.

3. How does pH affect tooth decay?

Ans. The pH of the mouth decreases as we eat more foods that contain acid, which encourages the growth of harmful bacteria and leads to tooth decay. Therefore, tooth decay results from the mouth’s pH being decreased.

Introduction

In today’s world, acid rain is a serious environmental issue. Midway through the 19th century, it was reported. As a result of excessive contaminants being removed from the atmosphere by both natural and man-made sources, this has occurred and therefore bringing down the pH of regular rainwater. There is no way to lessen the impact of natural sources, but there are various preventive steps that can be taken to lessen the impact of man-made sources. Since acid rain affects several ecosystems by lowering the pH of the material where it has been deposited, its prevention or mitigation is crucial.

What is acid rain?

Acid rain, a severe environmental issue, is caused by \(S{O_2}\) and \(N{O_x}\) emissions into the atmosphere. Acid rain is created when these substances interact with water vapour in the atmosphere. Normally, \(S{O_2}\) does not interact with water, but when it interacts with ozone, it changes into \(S{O_3}\), which then reacts with water to create sulphuric acid, resulting in acid rain. The environment is being threatened by acid rain. Water bodies and biological beings suffer greatly from acidification. According to reports, acidification causes a greater release of aluminium from rocks or soil and which eventually gathers or deposits on water bodies, posing a hazard to the creatures that drink the water.

What are the causes of acid rain?

• The atmospheric release of \(S{O_2}\) and \(N{O_x}\) chemicals results in acid rain. These chemicals come from a variety of sources, including both natural processes and human activity. 
• The natural sources include volcanic eruptions, sea spray, forest fires, etc. While man-made sources for sulphur dioxide include industrial combustion, coal burning from cars, oil refineries, home, and industrial boilers, automobiles, fertilizer plants, etc. 
• Natural sources of \(N{O_x}\) include bacterial activity, volcanic eruption, lightning, forest fires, etc. 
• When these substances are discharged in excess into the atmosphere, they react with the water that is already there to generate numerous acid molecules. 
• They are sulphuric acid and nitric acid. These further contribute to acidification and bring about various environmental issues.

What are the effects of acid rain?

• Nitrates are deposited on the soil as a result of acid rain, which also raises nitrogen saturation levels. This may also result in the loss of other significant ions from the soil, including calcium and magnesium ions that are beneficial to trees and plants. Additionally, acid rain removes the protective layer of trees, weakening them.
• Since acids take aluminium from soil and deposit it in water bodies, acid rain also has an impact on surface waters by raising the concentration of aluminium in the water bodies. The aquatic species that live in the water bodies will ultimately be impacted by this.
• Since the increased concentration of sulphuric acid and nitric acid promotes the corrosion of metals and fading of paints, acid rain impacts have been documented in man-made sculptures. 
• Due to the particle build-up, acid rain has an impact on people’s health who have asthma and emphysema. 
• Visibility is hampered by acid rain, which can often appear as fog.

Real-life examples of acid rain effects

• Acid rain has caused the sculpture at Oakland University in Rochester, Michigan, to degrade. 
• The US, Taiwan, Europe, Poland, and China’s southeast coast are some of the regions that are impacted. 
• The glossy feature of the Taj Mahal is presently deteriorating as a result of acid rain.
• Due to acid rain, the Statue of Liberty corroded and turned green. 
• Nearshore and coastal oceans are significantly acidified as a result of acid rain.

How to prevent acid rain?

Acid rain can be prevented only by reducing the emission of acid rain-causing particulates into the atmosphere. Only man-made sources can be reduced by performing several preventive methods. This can be done by, 

a) Reducing the sulphur-containing fuels in automobiles or switching to alternative sources. 

b) Scrubbers can be used for reducing the emission of \(S{O_2}\) into the atmosphere since they will attract sulphur particles. 

c) For reducing the emission of \(N{O_x}\) catalytic converters can be used, thereby converting it into \({N_2}\) and \({O_2}\). 

d) Liming water bodies can be done in reducing the impact of acid rain. 

e) The effect on metals due to acid rain can be reduced by coating them with corresponding materials.

Summary

Acid rain, a severe environmental issue, is caused by the atmosphere’s \(S{O_2}\) and \(N{O_x}\) emissions. The atmospheric release of \(S{O_2}\) and \(N{O_x}\) chemicals results in acid rain. Nitrates are deposited on the soil as a result of acid rain, which also raises nitrogen saturation levels. The glossy feature of the Taj Mahal is presently deteriorating as a result of acid rain. The effect on metals due to acid rain can be reduced by coating them with corresponding materials.

Frequently Asked Questions 

1. Write a note on the facts about acid rain.

Ans. Numerous substances, such as precipitation, snow, fog, and microscopic dry particles that fall on the surface of the planet, can carry acid rain to its surface. Additionally, regular precipitation has a pH of 5.6, whereas acid rain has a pH of roughly 4.6, which is a bigger difference and makes its effect more sensitive.

2. Can acid rain cause skin burns?

Ans. Since acid has a pH of 4.6, acid rain is not sufficiently acidic to cause skin burns. Additionally, it has no direct impact on humans. Patients with asthma and emphysema will experience issues if they come into contact with sulphur particles in the air.

3. Where does acid rain occur most often?

Ans. Acid rain is a widespread problem in places like Eastern Europe, and the US, and is now spreading to parts of India and China.