Question

16. Identify the oxidising agent (oxidant) in the following reactions

(a) Pb3O4 + 8HCl ⎯→ 3PbCl2 + Cl2 + 4H2O

(b) Mg + 2H2O ⎯→ Mg (OH)2 + H2

(c) CuSO4 + Zn ⎯→ Cu + ZnSO4

(d) V2O5 + 5Ca ⎯→ 2V + 5CaO

Answer 1

You can identify oxidising agent by a simple trick that is the substance having reduction is always the oxidising agent...

Answer 2

In a chemical reaction, the oxidation is the process in which the oxidation state of element increases whereas reduction process involves the reduction in the oxidation number. The substance that gets reduced is called as oxidizing agent or oxidant.  

Hence for an oxidant the oxidation number should decreases.

a) $P b^{+4}$ changes to $\mathrm{Pb}^{+2} \text { so } \bold{\mathrm{Pb}_{3} \mathrm{O}_{4}}$ is oxidant.

b) The oxidation number of H decreases from +1 to 0 so $\bold{\mathrm{H}_{2} \mathrm{O}}$ is oxidant.

c) The ‘oxidation number’ of Cu decreases from +2 to 0 so $\bold{\mathrm{CuSO}_{4}}$ is oxidant.  

d) $\bold{\mathrm{V}_{2} \mathrm{O}_{5}}$ is oxidant.