Calcium phosphate is present in tooth enamel. Its nature is

$(a)$ Study the following chemical equation:
$CaSO_4 \cdot 2H_2O \xrightarrow{373K} CaSO_4 \cdot \frac{1}{2}H_2O + \frac{3}{2}H_2O$
Name the reactant and the product. State one use of the product.

One of the constituents of baking powder is sodium hydrogencarbonate, the other constituent is

What will happen if a solution of sodium hydrogencarbonate is heated? Give the equation of the reaction involved.

State the number of water molecules present in crystals of washing soda and Plaster of Paris. What are these water molecules called?

Which of the following salts does not contain water of crystallisation?