Question

Give the balanced equation for the reaction between chlorine with cold NaOH and hot NaOH.

Answer 1

1. Reaction between chlorine with cold NaOH:

\[\ce{Cl2 + H2O -> HCl + HOCl}\]

\[\ce{HCl + NaOH -> NaCl + H2O}\]

\[\ce{HOCl + NaOH -> NaOCl + H2O}\]

Overall reaction:

\[\ce{Cl2 + \underset{\text{(Cold)}}{2NaOH} -> \underset{\text{(Sodium hypochlorite)}}{NaOCl} + \underset{\text{(Sodium chloride)}}{NaCl} + H2O}\]

Chlorine reacts with cold NaOH to give sodium chloride and sodium hypochlorite.

2. Reaction between chlorine with hot NaOH:

\[\ce{Cl2 + H2O -> HCl + HOCl}\]

\[\ce{HCl + NaOH -> NaCl + H2O}\]

\[\ce{HOCl + NaOH -> NaOCl + H2O}\]

\[\ce{3NaOCl -> NaClO3 + 2NaCl}\]

Overall reaction:

\[\ce{3Cl2 + \underset{\text{(Hot)}}{6NaOH} -> \underset{\text{(Sodium chlorate)}}{NaClO3} + \underset{\text{(Sodium chloride)}}{5NaCl} + 3H2O}\]

Chlorine reacts with hot NaOH to give sodium chlorate and sodium chloride.