Question

table salt becomes sticky on exposure to humid air during the rainy season

Answer 1

The table salt NaCl contains some salts of MgCl2 which has ability to absorb water from environment in the form of water of crystallization to form a hydrated salt.Water of crystallization is the number of water molecules, chemically combined in a definite molecular proportion, with the salt in its crystalline state. This water is responsible for the geometric shape and colour of the crystals.In rainy season, there is more water in surroundings. This is called hygroscopic nature of substance which makes the substance wet and sticky. In rainy season, there is more water in surroundings, hence more water is absorbed by NaCl.