Chemistry Class 10 Solutions Acids,Bases And Salts

1. When a solution is added to a cloth strip treated with onion extract, then the smell of onion cannot be detected. State whether the given solution contains an acid or a base.
Solution :
Base

2.When a solution is added to vanilla extract, then the characteristic smell of vanilla cannot be detected. State whether the given solution is an acid or a base.
Solution :
When Hydrochloric acid reacts with an active metal (like zinc), we observe that gas filled bubbles are formed on the surface of the metal. Pass the gas formed through soap solution. Then, bring a burning candle near the gas filled soap bubble. If the gas present in bubble burns with a ‘pop’ sound, then its hydrogen gas.

3.How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal ?
Solution :
Carbon dioxide (CO2) gas is evolved during the reaction. We pass this gas through lime water which turns milky because of the CO2 passing through it. If we keep on passing the gas through the milky lime water, it would become clear again.

4.Name the gas evolved when dilute HCl reacts with sodium hydrogencarbonate. How is it recognised ?
Solution :
Hydrochloric acid
(HCl) and Sulphuric acid (H2SO4) are strong acids.
Acetic acid (CH3COOH)
and Citric acid (C6H8O7) are weak acids.

5.Give the names and formulae of two strong acids and two weak acids.
Solution :
(a) Citric acid – Lemon.
(b) Oxalic acid – Tomatoes.
(c) Lactic acid – Sour milk or curd.
(d) Tartaric acid – Tamarind.