Chlorine is used to purify drinking …

Skeletal equation would be

{tex}{ Cl }_{ 2 }(aq)+{ SO }_{ 2 }(aq)+{ H }_{ 2 }O(l)\longrightarrow{ Cl }^{ - }(aq)+{ SO }_{ 4 }^{ -2 }(aq){/tex}

Reducing the half eqn is {tex}{ Cl }_{ 2 }(aq)\longrightarrow{ Cl }^{ - }(aq){/tex}

Balance the Cl atoms ,{tex} { { Cl }_{ 2 } } {\longrightarrow2Cl }^{ - }(aq){/tex}

Balance the oxidation number by adding the electrons.

{tex}{ Cl }_{ 2 }(aq)+2{ e }^{ - }\longrightarrow2{ Cl }^{ - }(aq).....(i){/tex}

Oxidation of half equation is{tex} \quad \overset { +4 }{ { SO }_{ 2 }(aq) } \longrightarrow { SO }_{ 4 }^{ -2 }(aq)+\overset { +6 }{ 2{ e }^{ - } } \quad \quad \quad{/tex}

Balance the oxidation number by adding the electrons.

{tex}{ SO }_{ 2 }(aq)\longrightarrow{ SO }_{ 4 }^{ -2 }(aq)+2{ e }^{ - }{/tex}

Balancing the charge by adding H^{ + }ions

{tex}{ SO }_{ 2 }(aq)\longrightarrow{ SO }_{ 4 }^{ -2 }(aq)+4H^{ + }(aq)+2{ e }^{ - }\quad.....(ii){/tex}

Balancing the oxygen atoms by adding the {tex}2 { H }_{ 2 }O{/tex}

Adding both the eqn (i) and eqn (ii), we get

{tex}{ Cl }_{ 2 }(aq)+{ SO }_{ 2 }(aq)+{ 2H }_{ 2 }O(l)\longrightarrow{ 2Cl }^{ - }(aq)+{ SO }_{ 4 }^{ -2 }(aq)+4H^{ + }(aq){/tex}

This is the balanced redox reaction.