Question

Which of the following reaction takes place at anode in hydrogen-oxygen fuel cell?

(a) \(H_2+\frac{1}{2}  O_2  \rightarrow H_2 O\)

(b) \(H_2 O \rightarrow H_2+ O_2\)

(c) \(H_2+2OH^-\rightarrow 2H_2 O+ 2e^-\)

(d) \(O_2+H_2 O+ 2e^-\rightarrow HO_2^-+ OH^-\)

I had been asked this question in class test.

Question is from Inorganic Chemical topic in division Inorganic Chemical Industries of Chemical Technology

Answer 1

Correct answer is (c) \(H_2+2OH^-\rightarrow 2H_2 O+ 2e^-\)

Explanation: \(H_2+\frac{1}{2}  O_2  \rightarrow H_2 O\) is an overall reaction whereas  \(H_2 O \rightarrow H_2+ O_2\)  is an unbalanced reaction. \(O_2+H_2 O+ 2e^-\rightarrow HO_2^-+ OH^-\)  is a reduction reaction which takes place at cathode, and \(H_2+2OH^-\rightarrow 2H_2 O+ 2e^-\) is the anodic reaction (oxidation reaction).