When sodium sulphide reacts with dilute hydrochloric acid, a gas with unpleasant smell is produced. This gas with unpleasant smell is:

Correct option is A

Correct option : (a) $$H_2 S$$

When sodium sulfide (Na₂S) reacts with dilute hydrochloric acid (HCl), the gas produced is hydrogen sulfide (H₂S), which is a colorless gas with a foul, rotten egg smell.

The chemical reaction can be written as:
Na2​S(aq)+2HCl(aq)→2NaCl(aq)+H2​S(g)

Information Booster : 

• ​Hydrogen sulfide (H₂S) is the gas produced when sodium sulfide (Na₂S) reacts with hydrochloric acid (HCl), as mentioned earlier.
  
• Hydrogen sulfide (H₂S)is toxic and has a distinct, unpleasant odor.
  
•  It has a characteristic foul odor, often likened to rotten eggs.​