Acids, Bases, and Salts - SS1 Chemistry Past Questions and Answers - page 4

Sour taste

 

Acids are named based on the anion they contain. The rules for naming acids depend on whether the anion is a polyatomic ion or a simple ion.

 

Naming Acids with Polyatomic Ions:

-       If the polyatomic ion ends in "-ate," the acid name is derived by replacing "-ate" with "-ic" and adding the word "acid." For example, sulphate becomes sulfuric acid (H2SO4).

-       If the polyatomic ion ends in "-ite," the acid name is derived by replacing "-ite" with "-ous" and adding the word "acid." For example, nitrite becomes nitrous acid (HNO2).

 

Naming Acids with Simple Ions:

-       If the anion is a simple ion, the acid name is derived by adding the prefix "hydro-" and replacing the suffix "-ide" with "-ic" and adding the word "acid." For example, chloride becomes hydrochloric acid (HCl).

 

Common Acids and their Properties:

1. Hydrochloric acid (HCl): Colourless, highly corrosive liquid. It is a strong acid commonly used in laboratory and industrial processes.
2. Sulfuric acid (H2SO4): Highly corrosive, oily liquid. It is a strong acid used in various industrial applications, such as manufacturing fertilisers and dyes.
3. Nitric acid (HNO3): Colourless to yellow liquid. It is a strong acid involved in the production of fertilisers, explosives, and various organic compounds.
4. Acetic acid (CH3COOH): Colourless liquid with a pungent odour. It is a weak acid found in vinegar and used in the production of plastics, solvents, and food preservatives.
5. Carbonic acid (H2CO3): Weak acid that exists only in solution. It is formed when carbon dioxide dissolves in water and plays a role in the carbon dioxide-bicarbonate buffer system in the body.

Bases are typically named following the rules of ionic compounds. They are named based on the cation they contain and are often referred to as hydroxides.

 

Naming Bases:

-       Bases containing a metal cation and the hydroxide ion (OH-) are named by combining the name of the metal with the word "hydroxide." For example, sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2).

 

Common Bases and their Properties:

1. Sodium hydroxide (NaOH): White, crystalline solid. It is a strong base and a common ingredient in cleaning agents, detergents, and drain cleaners.
2. Calcium hydroxide (Ca(OH)2): White, crystalline solid. It is a strong base commonly known as slaked lime and is used in construction, agriculture, and as a pH regulator.
3. Ammonium hydroxide (NH4OH): Colourless liquid with a strong odour. It is a weak base commonly referred to as ammonia water and is used in cleaning agents and household products.
4. Magnesium hydroxide (Mg(OH)2): White, powdery solid. It is a weak base and is commonly used as an antacid and in laxatives.
5. Aluminium hydroxide (Al(OH)3): White, gelatinous solid. It is a weak base and is used in antiperspirants, as an antacid, and in the production of aluminium compounds.

 

Bases are known for their ability to accept protons (H+) or donate hydroxide ions (OH-) in chemical reactions. They have properties that include a bitter taste, a slippery feel, and the ability to turn red litmus paper blue.