A compound that is a white solid which absorbs water vapour from the air is :

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Q: 18 (CDS-II/2013)
A compound that is a white solid which absorbs water vapour from the air is :

question_subject: 

Science

question_exam: 

CDS-II

stats: 

0,20,82,16,31,35,20

keywords: 

{'water vapour': [0, 0, 1, 2], 'calcium sulphate': [0, 1, 1, 7], 'calcium chloride': [0, 0, 1, 1], 'compound': [0, 0, 1, 1], 'sodium carbonate': [0, 0, 0, 1], 'sodium nitrate': [0, 0, 0, 1], 'air': [1, 0, 0, 0]}

The correct answer to the question is option 4 - Calcium sulphate.

Calcium sulphate is a white solid compound that has the property of absorbing water vapour from the air. This property is known as hygroscopicity. When exposed to moisture, calcium sulphate can form a hydrate, which is a compound that has water molecules attached to its structure. In the case of calcium sulphate, it can form different hydrates depending on the amount of water absorbed. One common hydrate is calcium sulphate dihydrate, also known as gypsum, which is used in the production of plasterboard and as a soil conditioner.

Option 1 - Sodium nitrate is not a white solid compound that absorbs water vapour from the air. Sodium nitrate is a white crystalline solid, but it is not hygroscopic.

Option 2 - Calcium chloride is a white solid compound that is known for its hygroscopic properties. However, in this question, the correct answer is calcium sulphate.

Option 3 - Sodium carbonate is a white solid compound, but it is not known for its ability to absorb water vapour. Sodium carbonate is commonly used as a cleaning agent and in the production of glass and paper.

In conclusion, calcium sulphate is the