Class 10 Solutions Acids,Bases And Salts

1.
What happens when an acid reacts with a base ? Explain by taking the example of hydrochloric acid and sodium hydroxide. Give equation of the chemical reaction which takes place. What is the special name of such a reaction ?
Solution :
When an acid reacts with a base, then a salt and water are formed. When hydrochloric acid reacts with sodium hydroxide solution, then a neutralisation reaction takes place to form sodium chloride and water.

Such a reaction is termed as neutralisation reaction.

2.What happens when an acid reacts with a metal oxide ? Explain with the help of an example. Write a balanced equation for the reaction involved.

Solution :
Acids react with metal oxides to form salt and water.
For example: Copper (II) Oxide, a metal oxide reacts with dilute hydrochloric acid to form copper chloride and water

3.
(a) What are organic acids and mineral acids ?
(b) Give two examples each of organic acids and mineral acids.
(c) State some of the uses of mineral acids in industry.
Solution :
(a) Organic acids are acids present in plant materials and animals. These are naturally occuring acids.
A mineral acid (or inorganic acid) is an acid derived from one or more minerals of the earth.
(b) Organic acids: Citric acid, lactic acid;
Mineral acids: Hydrochloric acid, sulphuric acid.
(c) Uses of mineral acids in industry:

1.  Sulphuric acid is used in the manufacture of fertilizers, paints, dyes, detergents etc.
2.  Nitric acid is used for making fertilizers, explosives, dyes and plastics.
3.  Hydrochloric acid is used for removing oxide film from steel objects, in textile, food and leather industries.

4.What is meant by strong acids and weak acids ? Classify the following into strong acids and weak acids :
HCl,   CH3COOH,   H2SO4,  HNO3,   H2CO3,   H2SO3Solution :
A strong acid is one that completely ionises in water to form a large amount of hydrogen ions whereas a weak acid only partially ionises in water and thus produces a small amount of hydrogen ions.
HCl, H2SO4, HNO3 are strong acids; CH3COOH, H2CO3, H2SO3 are weak acids.

5.Why do HCl, H2SO4, HNO3, etc., show acidic character in aqueous solutions while solutions of compounds like C6H12O6 (glucose) and C2H5OH (alcohol) do not show acidic character ?
Solution :
The acidic character of a substance is due to the presence of hydrogen ions [H+(aq) ions] in its aqueous solution. HCl, H2SO4 etc show acidic properties because they produce hydrogen ions when dissolved in water. The solution of compounds like alcohol and glucose do not show acidic character because they do not ionize in water to produce hydrogen ions or any other ions in solution.

6.What is a neutralisation reaction ? Explain with an example. Give the chemical equation of the reaction which takes place.
Solution :
The reaction between an acid and a base to form salt and water is called a neutralisation reaction. When hydrochloric acid reacts with sodium hydroxide solution, then a neutralisation reaction takes place to form sodium chloride and water.

7.Why should curd and other sour foodstuffs (like lemon juice, etc.) not be kept in metal containers (such as copper and brass vessels) ?
Solution :
Curd and other sour substances contains acids which can react with the metals of brass and copper vessels to form toxic (poisonous) metal compounds which can cause food poisoning and damage our health