The characteristic not related to alkali metal is

Consider the following statements.
$I$. $Cs^{+}$ ion is more highly hydrated than other alkali metal ions.
$II$. Among the alkali metals,only lithium forms a stable nitride by direct combination with nitrogen.
$III$. Among the alkali metals $Li, Na, K, Rb$,the metal $Rb$ has the highest melting point.
$IV$. Among the alkali metals $Li, Na, K, Rb$,only $Li$ forms peroxide when heated with oxygen.
Select the correct statement.

Salt cake is

Magnesium wire is heated in the atmosphere of $CO_2$ because

Consider the following reactions:
$Cs + O_2 \text{ (excess)} \rightarrow X$
$Na + O_2 \rightarrow Y$
Identify the correct statement about $X$ and $Y$.

Which of the following statements is incorrect?