Question

2. When sodium carbonate is added to
two tubes (A) containing dil. HCl and
(B) containing dil. NaOH, then which of
the following observations is correct?
(a) A yellow coloured gas liberated in test tube A
(b) A yellow coloured gas liberated in test tube
A and colourless gas in test tube8
(c) A colourless gas liberated in test tube A
(d) A colourless gas liberated in test tube 8

Answer 1

(c) A colourless gas liberated in test tube A as per given reactions.

• Sodium carbonate has chemical formula Na2CO3. It reacts with dilute hydrochloric acid to yield products namely sodium chloride, carbon dioxide and water.
• As carbon dioxide is colourless gas, it can be tested by passing it through lime water solution. Although carbon dioxide releases with brisk effervescence.

• On making it react with dilute sodium hydroxide, which is a base, no reaction takes place. Reason is owed to both the solutions being base.
• Sodium ions released as cations will react with different anions giving sodium product.