Q. Which of the following salts absorb moisture from air?

1. NaCl
2. CaCl₂
3. MgCl₂
4. KNO₃

Select the correct answer using the codes given below:
Answer: Only 2 and 3
Notes: CaCl₂ and MgCl₂ are deliquescent salts and readily absorb moisture from the air. NaCl is not typically deliquescent, and KNO₃ is stable under normal conditions and does not absorb moisture significantly. Therefore, only statements 2 and 3 are correct. Note: Pure sodium chloride (NaCl) is not a deliquescent substance, though it is hygroscopic and can absorb some moisture from the air. Deliquescent substances absorb enough moisture from the air to dissolve and form a solution. Pure NaCl does not absorb enough water to reach this point and remains crystalline under normal conditions.