A white solid is either $\ce{Na2O}$ or $\ce{Na2O2}$. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of white solid.
Identify the substance and explain with the help of balanced equation.
Explain what would happen to the red litmus if the white solid were the other compound.
From the solution and theoretical knowledge, I know the following:
$$\begin{align} \ce{Na2O2 + 2 H2O &-> 2NaOH + H2O2}\\ \ce{Na2O + H2O &-> 2NaOH} \end{align}$$
The aqueous solution of $\ce{Na2O}$ will convert red litmus into blue (basic property), so, the substance is $\bf{not}$ $\ce{Na2O}$ for sure.
But, how will it be $\ce{Na2O2}$? Why does the aqueous solution of sodium peroxide turns red litmus into white?