Answer:

1. Anhydrous salt-

A compound in which all water molecules are removed is called Anhydrous salt.

EG- anhydrous copper sulphate(CuSO4­) and anhydrous ferrous sulphate(FESO4)

2. Hydrated Salt-

A compound with one or more chemically combined water molecule.

EG- Copper sulphate pentahydrate (CuSO4.5H2O) and Ferrous sulphate(FeSO4.7H2O)

3. Water of crystallisation-

Water of crystallization is the amount of water molecules which are PRESENT in one formula unit of salt.

EG- PROTEINS with more than 50% of the water of crystallization and copper sulfate pentahydrate with five molecules of water of crystallization.

4. Deliquescent substance-

The substances which absorb moisture from the atmosphere on exposure to air. By absorbing moisture they may dissolve in the water absorbed and change into solution. Such substances are called deliquescent substances.

EG- Calcium chloride.

5. Hygroscopic substances-

The substances which do not undergo any change in physical state on the absorption of moisture from the atmospheric air. These are called hygroscopic substance.

EG- Calcium oxide, cobalt chloride

6.Effloroscent salts-

The salts which lose water of crystallization either completely of PARTIALLY on exposure to atmospheric air are called efflorescent substances.

EG- Na2CO3.10H2O loses nine water molecules on exposure to air and the remaining one water molecule on heating.