Question

1 gram of solid sodium chloride was taken in a clean and dry test tube and concentrated sulphuric acid was added to it.

1. Name the gas evolved in the reaction.
2. What will be observed when this gas is tested with (1) dry and (II) wet blue litmus paper?
   Write your conclusion about the nature (acidic/basic) of this gas.

Answer 1

When solid sodium chloride is reacted with concentrated sulphuric acid, the gas evolved in the reaction is hydrogen chloride (HCl) gas.

i. The gas evolved is hydrogen chloride (HCl) gas.

ii. When tested with blue litmus paper:

1. Dry blue litmus paper: No change will be observed because dry hydrogen chloride gas does not have acidic properties.
2. Wet blue litmus paper: The blue litmus paper will turn red, indicating that the gas is acidic when dissolved in water to form hydrochloric acid.

Conclusion: Hydrogen chloride gas exhibits acidic properties when dissolved in water, turning wet blue litmus paper red.