A white solid is either Na base 2O or Na base 2O base 2. A pice of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid.

(i) Identify the substance and explain with balanced equation.

(ii) Explain what would happen to the red litmus if the white solid were the other compound.

(i) The substance is Na base 2O base 2. When dissolved in water, the solution becomes alkaline with the liberation of H base 2O base 2 Na base 2O base 2 + 2H base 2O ? 2NaOH + H base 2O base 2

NOTE : Due to the alkaline solution, the red litmus paper will turn into blue, which subsequently changes into white due to oxidation caused by H base 2O base 2.

(ii) The substance Na base 2O merely produces alkaline solution and thus the red litmus paper will turn into blue.

Na base 2 + H base 2O ? 2NaOH