Question

Which of the following is/are the common electrochemical reactions that occur during corrosion?

(a) M==>M^++ne

(b) 2H^++2e=>H2

(c) O2+4H^++4e==>H2O

(d) M==>M^++ne, 2H^++2e=>H2 and O2+4H^++4e==>H2O

I got this question during an interview.

My question comes from Cathodic and Anodic Protection topic in portion Corrosion Prevention of Corrosion Engineering

Answer 1

Correct answer is (d) M==>M^++ne, 2H^++2e=>H2 and O2+4H^++4e==>H2O

Easiest explanation: The common electrochemical reactions that occur during corrosion are:  

M==>M^++ne (metallic reduction or anodic reaction)

2H^++2e=>H2 (hydrogen evolution or cathodic reaction)

O2+4H^++4e==>H2O (oxygen reduction or cathodic reaction)