Question

1. 1. Balance the following skeleton reactions and identify the oxidizing and reducing agents: (a) Mn+ (aq) + BiO3 (aq) →MnO4 (aq) + Bit (aq) (acidic) (b) Fe(OH)2(s) + Pb(OH)3 (aq) Fe(OH)3(s) + Pb(s) (basic)

Answer 1

An oxidizing agent, gains electrons and is reduced in a chemical reaction. Also known as the electron acceptor,

A reducing agent  loses electrons and is oxidized in a chemical reaction.

(a) Mn²⁺ + BiO₃^-$\rightarrow$ MnO₄^- + Bi³⁺

In the above reaction the oxidation state of Mn increases from +2 state to +7 state. It has lost electrons and is getting oxidized. Hence called as a reducing agent. However, the oxidation state of Bi decreases from 5 to 3. Two electrons are added up and is getting reduced. Therefore Bi is an oxidizing agent.

The balance equation is as follows

3Mn²⁺ + 4BiO₃^-$\rightarrow$ 3MnO₄^- + 4 Bi³⁺

^{(b) Fe(OH)₂ (s) + Pb(OH)₃- $\rightarrow$ Fe(OH)₃ (s) + Pb(s)}

In the above reaction the oxidation state of Fe increases from +2 state to +3 state. It has lost electrons and is getting oxidized. Hence called as a reducing agent. However, the oxidation state of Pb decreases from 2 to 0. Two electrons are added up and is getting reduced. Therefore Pb is an oxidizing agent.

The balance equation is as follows

^{3Fe(OH)₂ (s) + Pb(OH)₃- $\rightarrow$ 3 Fe(OH)₃ (s) + Pb(s)}