How can you distinguish chlorine gas from sodium chloride using litmus paper?

• A. Chlorine bleaches litmus; sodium chloride causes no change.
• B. Chlorine turns litmus blue; sodium chloride turns litmus red.
• C. Both bleach litmus to colorless.
• D. Litmus turns red with both.

Answer: (A)

Chlorine gas acts as a bleaching agent for litmus paper, removing its color. Sodium chloride doesn’t react with litmus, so the paper stays the same. So, chlorine gas will make litmus go colorless, while sodium chloride causes no change.