There is no change in the colour of red litmus and blue litmus paper when introduced into an aqueous solution of sodium chloride. After passing direct current through the same solution, red litmus changes to blue colour. Which product is responsible for this change ? Mention any two uses of this product.

Explanation

There is no change in the colour of red litmus and blue litmus paper when introduced into an aqueous solution of sodium chloride because sodium chloride is neutral in nature. If electric current is passed through aqueous solution of NaCL then the products are sodium hydroxide, chlorine and Hydrogen.
`2NaCl (aq) + 2H_(2)O(l) rarr 2NaOH(aq) + Cl_(2)(g) + H_(2)(g)`
Since sodium hydroxide is basic in nature, red litmus turns blue. Uses of Sodium hydroxide :
(i) Used in preparation of soaps and detergents.
(ii) Used in manufacture of paper.