An element $A$ of group $1$ shows similarity to an element $B$ belonging to group $2$. If $A$ has maximum hydration enthalpy in group $1$,then $B$ is:

Which one of the following dissolves in hot concentrated $NaOH$ solution?

Give two uses of $KOH$.

When $Zn$ is treated with excess of $NaOH$,the product obtained is

Select the correct statement from the following.

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 :