Question

Which of the following type of compounds act as an inhibitor for hydrogen-ion reduction?

(a) Sulfide ions

(b) Phosphorous compounds

(c) Arsenic compounds

(d) Sulfide ions, phosphorous and arsenic compounds

I had been asked this question at a job interview.

The question is from Eight Forms topic in section Eight Forms of Corrosion of Corrosion Engineering

Answer 1

Right answer is (d) Sulfide ions, phosphorous and arsenic compounds

Explanation: Hydrogen atoms diffuse into steel and other metals, which results in hydrogen blistering and hydrogen embrittlement. These inhibitors such as sulfide ions (polysulfide ion), phosphorous, and arsenic compounds reduce the rate of hydrogen-ion reduction.