Question

In each of the following reactions, identify the reactant that is oxidized and the reactant that is reduced:

(its multiple choice)

Number 1:

Br2(g)+2KI(aq)→2KBr(aq)+I2(s)

I− (in KI) loses electrons and is oxidized. Br2 gains electrons and is reduced.

Br2 gains electrons and is oxidized. I− (in KI) loses electrons and is reduced.

I− (in KI) gains electrons and is oxidized. Br2 loses electrons and is reduced.

Br2 loses electrons and is oxidized. I− (in KI) gains electrons and is reduced. Number 2: Sn(s)+Cu2+(aq)→Sn2+(aq)+Cu(s) Sn loses electrons and is oxidized. Cu2+ gains electrons and is reduced. Cu2+ gains electrons and is oxidized. Sn loses electrons and is reduced. Cu2+ loses electrons and is oxidized. Sn gains electrons and is reduced. Sn gains electrons and is oxidized. Cu2+ loses electrons and is reduced. Number 3: Fe(s)+CuSO4(aq)→FeSO4(aq)+Cu(s) Fe loses electrons and is oxidized. Cu2+ (in CuSO4) gains electrons and is reduced. Cu2+ (in CuSO4) gains electrons and is oxidized. Fe loses electrons and is reduced. Cu2+ (in CuSO4) loses electrons and is oxidized. Fe gains electrons and is reduced. Fe gains electrons and is oxidized. Cu2+ (in CuSO4) loses electrons and is reduced.

Answer 1

Br₂(g)+2KI(aq)→2KBr(aq)+I₂(s)

Bromine gains electron and the oxidation number decreases from 0 to -1 (Oxidation number of Br in KBr is -1).Iodine loses electron and the oxidation number increases from -1(Oxidation number of iodine in KI is -1) to 0. Thus, Bromine is getting reduced and Iodine is getting oxidized

Sn(s)+Cu²⁺(aq)→Sn²⁺(aq)+Cu(s)

Tin (Sn) loses two electron and the oxidation number increases from 0 to +2 .Copper(Cu) gains two electron and the oxidation number decreases from +2 to 0. Thus, Tin (Sn) is getting oxidized and Copper is getting reduced.

Fe(s)+CuSO₄(aq)→FeSO₄(aq)+Cu(s)

Fe loses two electron and the oxidation number increases from 0 to +2 (Oxidation number of Fe in FeSO₄ is +2) .Copper(Cu) gains two electron and the oxidation number decreases from +2(Oxidation number of Cu in CuSO₄) to 0. Thus, Fe is getting oxidized and Copper is getting reduced.