Question

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 the change mention any two uses of this product​

Answer 1

Sodium Hydroxide is responsible for changing the red litmus into blue colour.

When sodium chloride is electrolysed, hydrogen gas is formed at the negative electrode and chlorine gas is formed at the positive electrode along with formation of sodium hydroxide.

Uses of sodium hydroxide :

● Sodium Hydroxide is used as drain cleaners in our day to day life.

● it also serves as a helpful agent in water treatment plants.

● another important field where Sodium Hydroxide is used or is helpful is the field of oil refining.

Answer 2

There is no change in the colour of red litmus and blue Litmus Paper when introduced into an aqueous solution of sodium chloride which implies that 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.

Chemical equation :

2NaCl (aq) +2H2O-(l)---->2 NaOH(aq) + Cl2(g) +H2(g)

so production of sodium hydroxide is responsible for change of red litmus to blue .

Hence Sodium hydroxide is basic in nature.

Uses of Sodium hydroxide :

• Used in preparation of soaps and detergents.

• used in manufacture of paper.

• used in preparation of Rayon fibre.