Question

Commercial common salts become slightly damp on keeping. This is due to the fact that:

• A. common salt is hygroscopic
• B. common salt contains some impurities which are hygroscopic
• C. common salt is efflorescent
• D. common salt is crystalline

Answer 1

Answer: (B)

common salt contains some impurities which are hygroscopic

Commercial common salt commonly becomes slightly damp on keeping because common salt contains some impurities like $MgC{l}_2$ and $CaC{l}_2$ which are hygroscopic in nature and absorb moisture from the atmosphere.
Hence, option B is correct.