Question

In standardization of Na₂S₂O₃ using K₂Cr₂O₇ by iodometry, the equivalent weight of K₂Cr₂O₇ is

(a) MW/2

(b) MW/3

(c) MW/6

(d) MW/1

Answer 1

Correct option is (c) MW/6

During this reaction, Cr₂O₇^2- reacts in the following manner.

Cr₂O₇^2- + 14H⁺ + 6e^- → 2Cr³⁺ + 7H₂O

\(\therefore\) Eq. wt. of K₂Cr₂O₇ = Mol. wt/6