Identify the substance oxidised substance reduced, oxidising agent, and reducing agent for each of the following reactions:
a. `2AgBr(s) + C_(6)H_(6)O_(2)(aq) rarr2Ag(s) + 2HBr(aq) + C_(6)H_(4)O_(2)(aq)`
b. `HCHO(l) + 2[Ag(NH_(3))_(3)]^(o+) + 3 overset(Θ)(OH)(aq) rarr 2Ag(s) + HCOO^(Θ)(aq) + 4NH_(3)(aq) + 2H_(2)O(l)`
c. `HCHO(l)+ 2Cu^(2+)(aq) + 5overset(Θ)(OH) (aq) rarr Cu_(2)O(s)+ HCOO^(Θ)(aq) + 3H_(2)O(l)`
d. `N_(2)H_(4)(l) + 2H_(2)O_(2)(l) rarrN_(2)(g) + 4H_(2)O(l)`
d. `Pb(s) + PbO_(2)(s) + 2H_(2)SO_(4)(aq) rarr 2PbSO_(4)(s)+2H_(2)O(l)`

Explanation

(a) Oxidised substance `to C_(6)H_(6)O_(2)`
Reduced substance `to AgBr`
Oxidising agent `to` AgBr
Reducing agent `to C_(6)H_(6)O_(2)`
(b) Oxidised substance `to ` HCHO
Reduced substance `to`
`[Ag(NH_(3))_(2)]^(+)`
Oxidising agent `to`
`[Ag(NH_(3))_(2)]^(+)`
Reducing agent `to HCHO`
(c) Oxidised substance `to` HCHO
Reduced substance `to Cu^(2+)`
Oxidising agent `to Cu^(2+)`
Reducing agent `to HCHO`
(d) Oxidising substance `to N_(2)H_(4)`
Reduced substance `to H_(2)O_(2)`
Oxidising agent `to H_(2)O_(2)`
Reducing agent `to N_(2)H_(4)`
(e) Oxidised substance `to` Pb
Reduced substance `to PbO_(2)`
Oxidising agent `to PbO_(2)`
Reducing agent `to` Pb