Question

Which of the following products are obtained when a zinc metal is dipped in dilute HCl solution?

(a) H2, ZnCl2

(b) Cl2, ZnH2

(c) H2, Cl2 and ZnH2

(d) Zn, H2 and Cl2

I had been asked this question in an interview.

The origin of the question is Corrosion Principles topic in division Corrosion Principles of Corrosion Engineering

Answer 1

Correct answer is (a) H2, ZnCl2

The best I can explain: When zinc is placed in dilute hydrochloric acid, a vigorous reaction occurs. Hydrogen gas is evolved and the zinc dissolves, by forming a solution of zinc chloride.

Anodic reaction: Zn==>Zn^+2+2e(Zn^+2+2Cl^– ==>ZnCl2)

Cathodic reaction: 2H^++2e==>H2