Question

In the reduction of dichromate by Fe (II), the number of electrons involved per chromium atom is

(a) 3

(b) 1

(c) 2

(d) 4

Answer 1

Correct option is (a) 3

Reduction process:

\(Cr_2O_7^{2-} + 8H^+ + 5e^- \longrightarrow 2Cr^{3+} + 7H_2O\)

So, 3 electrons per Cr atom is used.