Chlorine is used to purify drinking water. Excess of chlorine is harmful . The excess of chlorine is removed bt treating with sulphur dioxide . Present a balanced equation for this redox change taking place in water.

Explanation

The reaction that occurs when `SO_(2)`is used to remove excess `CI_(2)`drinking water is -
`CI_(2)(aq)+SO_(2)(aq)to2CI^(-)(aq) +SO_(4)^(2-)(aq)`
Oxidation reaction `overset(+4)SO_(2)(aq)overset(+6)SO_(4)^(2-)(aq)`
To balancing charge O-atoms ,we add `2H_(2)O `to the left hand side and `4^(+)` to the right hand side
`SO_(2)(aq)+2H_(2)O(l)toSO_(4)^(2-)to(aq)+4H^(+)(aq)` Balancing charge on both sides ,we have
Reduction reaction : `CI_(2)(aq)+2eto2CI^(-)(aq)`
Adding equation (1) to equation (2) ,we have
`CI_(2)(aq)+SO_(2)(aq) +2H_(2)O(l)toSO_(4)^(2-)(aq)+2CI ^(-)(aq)+4H^(+)(aq)`
This is the balanced equation for the equation for the reaction .