question_answer

Which three chemical substances are obtained when electricity is passed through an aqueous solution of brine? Write one industrial use of each.

Answer:

When electricity is passed through a concentrated solution of sodium chloride (called brine), it decomposes to form sodium hydroxide, chlorine and hydrogen gas.

\[2NaCl(aq)+2{{H}_{2}}O\xrightarrow{Electricity}2NaOH(aq)+C{{l}_{2}}\uparrow +{{H}_{2}}\uparrow \]

(i) Use of Sodium hydroxide (NaOH). It is used for making soaps and detergents.

(ii) Use of Chlorine \[\mathbf{(C}{{\mathbf{l}}_{\mathbf{2}}}\mathbf{)}\]). It is used in the production of bleaching powder.

(iii) Use of hydrogen gas \[\mathbf{(}{{\mathbf{H}}_{\mathbf{2}}}\mathbf{)}\]. It is used to make ammonia for fertilisers; used as a fuel or margarine.