Tag: Bases

Introduction

“An acid and a base react in chemistry to produce salt as a by-product. The negative ion (anion) of an acid and the positive ion (cation) of a base combine to form a salt. When an acid and a base come into contact, a neutralisation reaction takes place.” Table salt, composed of sodium chloride, is also referred to as salt. Most salts completely dissolve into negatively and positively charged ions when in solution or the molten state, making them excellent electrolytes.

What are the characteristics of salt?

• Salts are created when sodium and chloride combine.
• Ion bonds are electrostatic forces that bind ions together. They are drawn to one another by the opposite charges on the two ions.
• Saltwater is a good conductor of electricity, and the ionic compounds are neutral with no charge when they contain an equal number of opposite charges.
• Salts have an ionic character because they contain ions.
• Salt is a white, odourless, and salty tasting solid that is hard, crystalline, and brittle.

Explain the different types of salts 

• Normal Salts-Electrical neutrality is present in typical salts. When acids and bases balance each other out, these salts are produced.  Metallic ions completely replace hydrogen ions. Some examples, are NaCl, \(KN{O_3}\), \(CuS{O_4}\), etc.
• Basic Salt- A basic salt is the type of substance produced when a weak acid and a strong base react. This reaction creates a salt that is more basic. The pH of this salt is higher than 7. Sodium acetate (\(C{H_3}COONa\)), is a basic salt.
• Acidic Salt-Strong acids are neutralised by weak bases to form acidic salts. Such salt can dissolve in water and produce an acidic solution. Ammonium chloride (\(N{H_4}CI\)) is an acidic salt that is created when HCl, a strong acid, and \(N{H_4}OH\) (a weak base) react.
• Double Salt- A salt that contains two or more different cations or anions is referred to as a double salt. Examples of double salts include alums and Tutton’s salts.
• Mixed Salt- A salt that has a fixed ratio of two salts is called mixed salt. There is a common cation or anion in this mixed salt. Bleaching powder and sodium potassium carbonate are a couple of examples of mixed salts.
• Complex Salt- A complex salt is a substance made up of ligands surrounding a central metal atom in coordination bonds. Another name for this is a coordination compound. Because of the complex structure and the bonds between the cations and anions, this substance is known as a complex salt.

Explain the process of Neutralisation Reaction

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 neutralisation 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.

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

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

Summary

Sodium chloride, also known as table salt, is a substance that we are all familiar with. We frequently season and preserve food with it. Other salt varieties and their applications, such as in the production of polyester fabrics, fertilisers, and dyes, are less well-known. Salts are frequently the result of an acid-base neutralisation reaction.

Frequently Asked Questions

1. How to tell whether something is neutral, acidic, or basic.

Ans. If the pH of a solution is lower than 7, it is said to be acidic. If the pH is 7, the solution is neutral; if it is higher than 7, the solution is basic.

2. Write five reasons why salt is important for the body.

Ans. Salt helps you stay hydrated, promotes good vascular health, balances electrolytes and prevents muscle cramping, supports a healthy nervous system, and improves sleep.

3. Is salt a chemical element?

Ans. Table salt is made up of the element sodium (Na) and chloride (Cl). Both elements are found bound together in nature as the compound sodium chloride, rather than occurring separately and freely.

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

The most important class of compounds in chemistry are acids and bases. Acids and bases are essential to practically every natural system, including human survival and the functioning of rocks and oceans. You must have come across acid and bases when you tasted lemon or washed your hands with soaps. Acids are sour and can be dangerously corrosive; bases are slippery and can be corrosive as well. In science, compounds are typically categorized as bases, acids, or neutral. The pH scale is used to determine how strong an acid or base is.

Acids

1. Acids release hydrogen ions or a proton when combined with water.

2. They exhibit a pH below 7 and turn blue litmus red. 

3. Arrhenius state that “those substances which give hydrogen ions \({H^ + }\) in aqueous solution” are known acids.

\[HA{\rm{ }} + {\rm{ }}{H_2}O{\rm{ }} \to {\rm{ }}{A^ – } + {\rm{ }}{H_3}{O^ + }\]

4. The common acids which we can use in the laboratory are—Hydrochloric acid (HCl), Nitric acid (\(HN{O_3}\)) and Sulphuric acid (\({H_2}S{O_4}\)).

Uses of Acids

Acid	Uses
Sulphuric Acid, H2SO4	Used as solvent
Formic Acids, HCOOH	Used for tanning and dyeing
Hydrochloric Acid, HCl	Used as Cleaner
Benzoic Acid, C6H5COOH	Used as food preservatives and in dyeing
Nitric Acid, HNO3	Used in Fertilizer, dyes, and plastics

Bases

1. Bases are substances that release hydroxyl ions when combined with water to form an aqueous solution. 

2. They exhibit a pH level above 7 and turn red litmus to blue. 

3. A base has a basic group that separates in an aqueous media or a dissociable hydroxyl group (Arrhenius base). 

4. Metal hydroxides are mostly basic and rapidly produce hydroxyl ions in an aqueous solution. The majority of basic hydroxides are formed by alkali metals and a few alkaline earth metals.

\[BOH\left( {aq} \right){\rm{ }} \to {\rm{ }}{B^ + }\left( {aq} \right){\rm{ }} + {\rm{ }}O{H^ – }\left( {aq} \right)\;\]

5. Sodium hydroxide, potassium hydroxide, and ammonium hydroxide are some examples of bases. 

Uses of Bases

Bases	Uses
Potassium Hydroxide, KOH	Soaps and Batteries
Ammonia NH3	Fertilizer
Calcium Hydroxide, Ca(OH)2	Mortar and Plaster
Magnesium Hydroxide, Mg(OH)2	Detergent
Sodium Carbonate Na2CO3	Detergent

Properties of Acids and Bases

Properties	Acid	Base
Taste	Sour	Bitter
pH value	less than 7	greater than 7
Electric conductivity	Good conductor	Good conductor
Test with litmus paper	Turn red litmus to blue.	Turns blue litmus to red.
Touch	–	Slippery

The similarity between an acid and a base

1. They both react with litmus.

2. They both are compounds

3. Likewise, they both release ions in their solution

4. Forms salt and water when combined. For example, when Ammonium hydroxide reacts with Hydrochloric acid, it gives Ammonium Chloride. 

\[N{H_4}OH{\rm{ }}\left( {aq} \right)\;{\rm{ }} + {\rm{ }}HCl\left( {aq} \right)\;\, \to {\rm{ }}N{H_4}Cl{\rm{ }}\left( s \right){\rm{ }} + {H_2}O{\rm{ }}\left( l \right)\]

Summary

Acidic substances are usually identified by their sour taste. An acid is a molecule which can donate an \({H^ + }\) ion and can remain energetically favourable after a loss of \({H^ + }\). Acids are known to turn blue litmus red.

Bases, on the other hand, are characterized by a bitter taste and a slippery texture. A base that can be dissolved in water is referred to as an alkali. When these substances chemically react with acids, they yield salts. Bases are known to turn red litmus blue.

Frequently Asked Questions

1. Which acid or base, when dissolved in water, releases hydroxyl ions?

Ans. Bases are chemicals that dissolve in water to produce hydroxyl ions, or \(O{H^ – }\), and are also referred to as alkalis.

2. What kind of salt is produced when a strong acid reacts with a weak base?

Ans. The salts are known as acidic salts because they are formed when strong acids and weak bases react. Every salt has a pH that is under 7. Similar to this, many salts’ aqueous solutions have a pH of 7 and are naturally neutral.

3. Which has a sour taste between acid and base?

Ans. Bases have a bitter taste, while acids have a sour taste. Acid always has a pH value lower than 7, which causes it to turn blue litmus paper red.