For the followin gredox reaction:
`2AI(s)+3CuSO_(4)rarrfaI_(2)(sO_(4))(aq)+3Cu(s)`
(i) Write the oxidation and reduction half reactions,
(ii) Which sp[ecieds acts as reducing angent and which as an oxidising agent?
(iii) What is the role of `SO_(4)^(2)` ions in the reaction?

Explanation

`(i) AI^(s)rarrAI^(3)(aq)+3e^(-)`(oxidation half reaction)
`Cu^(2)+(aq)+SO_(4)^(2)-(aq)+2e^(-)rarrCu(aq)+SO_(4)^(2)-(aq)` (reduction half reaction)
(ii) AI acts as reducing agent as it loses electrons. `CU^(2+)` ions acts as oxidishing agent since they gaiun electrons.
(iii) `SO_(4)^_(2)` ions are the common ion and have no role to play in the redox reaction .These are also called 'spectator ions '.
common ions which do not paritcipate in oxidation and reduction half reacitons, are know as spector ions