Name the constituents of baking powder. 

Why is sodium chloride added to the solution during the preparation of soap?

Name the compound of sodium which loses its water of crystallisation when exposed to air.

Name the substance which when heated with chlorine gas gives bleaching powder.

Name the compound of sodium which is used to make borax and glass. (Sodium carbonate decahydrate/ Sodium hydroxide)

Name any two substances which do not contain water of crystallization.

$$\begin{gathered} \mathrm{A} : {\mathrm{NaHCO}}_3 \\ \mathrm{B} : {\mathrm{NaCO}}_3 \\ \mathrm{A} : {\mathrm{Na}}_2{\mathrm{CO}}_3 \end{gathered}$$

Choose correct answer as $\mathrm{A}, \mathrm{B}$ or $\mathrm{C}$.