Question

Is it essential that oxidation and reduction must occur side by side in a chemical reaction? Explain

Answer 1

In a chemical reaction, if one substance is oxidised, the other substance must necessarily be reduced. This is because the electrons lost during oxidation are simultaneously gained during reduction and vice versa.

For example, Zinc reacts with copper sulphate to form zinc sulphate and copper.

CuSO4 + Zn → ZnSO4 + Cu

Cu + 2SO42- + Zn →Zn + 2SO42- + Cu

Writing the half reaction,

Zn → Zn2+ + 2e- (Oxidation)

Cu2+ + 2e-→ Cu (Reduction)

They occur simultaneously as

Cu2+ + Zn→ Zn2++ Cu

Thus, oxidation and reduction always occur simultaneously.