Hydroxide of which alkali metal is used in the manufacture of soft soap?

In which of the following processes,fused sodium hydroxide is electrolysed at a $330 \ ^oC$ temperature for the extraction of sodium?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$(a)$ $Li$	$(i)$ photoelectric cell
$(b)$ $Na$	$(ii)$ absorbent of $CO_{2}$
$(c)$ $K$	$(iii)$ coolant in fast breeder nuclear reactor
$(d)$ $Cs$	$(iv)$ treatment of cancer
	$(v)$ bearings for motor engines

Choose the correct answer from the options given below:

Identify the correct order of standard enthalpy of formation of sodium halides.

The solubility of $Na_2SO_4$,$BeSO_4$,$MgSO_4$ and $BaSO_4$ in water follows the order:

Which metals upon heating in the presence of air followed by hydrolysis give ammonia?