Which of the alkali metals has the lowest melting point?

Two elements $A$ and $B$ have similar chemical properties. They do not form solid hydrogencarbonates,but react with nitrogen to form nitrides. $A$ and $B,$ respectively,are :

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

List-$I$	List-$II$
$(a)$ $Li$	$(i)$ Poor water solubility of $I^{-}$ salt
$(b)$ $Na$	$(ii)$ Most abundant element in cell fluid
$(c)$ $K$	$(iii)$ Bicarbonate salt used in fire extinguisher
$(d)$ $Cs$	$(iv)$ Carbonate salt decomposes easily on heating

Choose the correct answer from the options given below :

Which of the following compounds on heating does not produce a metal oxide?

When a moderate amount of sodium metal is dissolved in liquid ammonia at low temperature,which of the following is $NOT$ obtained?

How does the ionization energy of Group $1$ elements change down the group?