In the reaction given below identify the species undergoing oxidation and reduction :
(i) `CH_(4)(g)+2O_(2)(g)rarr CO_(2)(g)+2H_(2)O(l)`
(ii)`H_(2)S(g)+O_(2)(g)rarr2S(s)+2H_(2)O(l)`
(iii)`CH_(2)=CH_(2)(g)+H_(2)(g)rarrH_(3)C-CH_(3)(g)`
(iv)`HgO(s)rarr2Hg(l)+O_(2)(g)`
(v)`Mg(s)+S(s)rarr MgS(s)`

Explanation

(i) `CH_(4)` is oxidised to `cO_(2)` while `O_(2)` is reduced to `H_(2)O` (ii) `H_(2)S` us ixudused ti S wile `O_(2)` is reduced to `H_(2)O` (iii) `CH_(2)=cH_(2)` is rduced to `CH_(3) rarr CH_(3)` while `H_(2)` is oxidised to `CH_(3)-CH_(3)`
(iv) `Hg^(2+)` is reduced to Hg whle `O^(2-)` is oxidised to `O_(2)` (v)Mg is oxiised to `Mg^(2+)` while S is reduced to `S^(2-)`