Question

Combine the following two reactions to obtain a balanced overall redox reaction.

Zn → Zn2++2e− and H++e− → H

Express your answer as a chemical formula.

Answer 1

We know that oxidation is loss of electrons

So oxidation half reaction is

$Zn\rightarrow Zn^{2+}+2e^-$.....(1)

Reduction is gain of electrons

So reduction half reaction is

$H^++e^-\rightarrow H$

Multiply reduction half reaction by 2

$2H^++2e^-\rightarrow 2H$.......(2)

Add (1) and (2)

$Zn+2H^++2e^-\rightarrow Zn^{2+}+2e^-+2H$

Cancel the electrons

$Zn+2H^+\rightarrow Zn^{2+}+2H$

This is the overall balanced redox reaction

To express it as a chemical formula, we can combine Zn²⁺ with 2H to form ZnH₂.