Question

What is the cathodic and anodic reactions respectively of Cu-Ag system?

(a) Ag==>Ag^+2+2e and Cu^+2+2e==>Cu

(b) Cu==>Cu^+2+2e and Ag==>Ag^+2+2e

(c) 2Ag^+1+2e==>2Ag and Cu==>Cu^+2+2e

(d) 2Ag==>2Ag^+1+2e and Cu^+2+2e==>Cu

I had been asked this question during an interview for a job.

Question is taken from Modern Theory Principles in portion Modern Theory Principles of Corrosion Engineering

Answer 1

The correct choice is (c) 2Ag^+1+2e==>2Ag and Cu==>Cu^+2+2e

For explanation I would say: Standard hydrogen potential of silver (Ag) is +0.80V and copper is +0.34V.

Cathodic reaction: 2Ag^+1+2e==>2Ag

Anodic reaction: Cu==>Cu^+2+2e