Question

What happens when a concentrated solution of sodium chloride (brine) is electrolysed? Write the equation of the reaction involved.

Answer 1

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

\[\ce{\underset{(Brine)}{\underset{Sodium chloride}{2NaCl_{(aq)}}} + \underset{Water}{2H2O_{(l)} ->[Electricity][(Electrolysis)]} \underset{(Caustic soda)}{\underset{Sodium hydroxide}{2NaOH_{(aq)}}} + \underset{Chlorine}{Cl2_{(g)}} + \underset{Hydrogen}{H2_{(g)}}}\]