Which gas/gases evolve$(s)$ when sodium metal is reacted with water at room temperature?

Ions of an element of group $1$ participate in the transmission of nerve signals and transport of sugars and amino acids into cells. This element imparts yellow colour to the flame in flame test and forms an oxide and a peroxide with oxygen. Identify the element and write chemical reaction to show the formation of its peroxide. Why does the element impart colour to the flame?

Identify the incorrect statement from the following.

Which of the following reacts with a solution of caustic soda upon heating to produce a combustible gas?

The number of alkali metal$(s)$,from $Li$,$K$,$Cs$,$Rb$ having ionization enthalpy greater than $400 \ kJ \ mol^{-1}$ and forming stable super oxide is $.......$

Match Column $-I$ with Column $-II$ :

Column $-I$	Column $-II$
$(a)$. Super oxide	$(p)$. $Na_2O_2$
$(b)$. Peroxide	$(q)$. $CO_2$
$(c)$. Dioxide	$(r)$. $C_3O_2$
$(d)$. Sub oxide	$(s)$. $CsO_2$