Question

A white solid is either$N{a_2}O$ or $N{a_{2}}{O_2}$. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid. If true enter 1 else 0.

Answer 1

A red litmus paper is generally employed to detect the alkaline pH and it turns into a shade of blue in the presence of the basic solution. On the other hand, a blue litmus paper is usually utilised to detect the acidic pH and it turns into a shade of red in the presence of acidic solution.

Complete answer:
In the question, we are given two substances i.e. $N{a_2}O\;$ or $N{a_{2}}{O_2}$ which appear as white solid. Let us discuss each of these substances one by one.
The first substance is $N{a_2}O\;$. When $N{a_2}O\;$ is dissolved in water, it leads to the formation of $NaOH$ which is a strong base and it turns the red litmus paper to blue.
$N{a_2}O + {H_2}O\; \to \;2NaOH$
The second substance given is $N{a_{2}}{O_2}$. When $N{a_{2}}{O_2}$ is dissolved in water, it leads to the formation of $NaOH$ and ${H_2}{O_2}$. As we know, $NaOH$ is a strong base and ${H_2}{O_2}$ is a weak acid. ${H_2}{O_2}$ possess strong oxidizing properties due to which it has a bleaching characteristic so it turns the colour of red litmus paper to white.
$N{a_2}{O_2} + 2{H_2}O\; \to \;2NaOH + {H_2}{O_2}$

So 1 has to be entered.

Note:
Red litmus paper is used to indicate the alkalinity of a substance with a change to blue colour. Litmus paper is generally red below a pH of 4.5 while blue above pH of 8.3. When the litmus paper turns purple, this means the pH is near neutral. If the red litmus paper does not change its colour, it indicates that the sample is an acid.