Answer to Question #213668 in General Chemistry for rahul

Question

Calculate the oxidation of Cr in Cr₂O₇^2-

Answer 1

In the dichromate ion, the oxidation number of chromium is+6. The sum of the oxidation numbers in Cr₂O₇^2-, a polyatomic ion, is -2, the charge of the ion.

We assign -2 as the oxidation number for each oxygen, and x as the oxidation number of each chromium and write the following equation: 2x + 7(-2) = - 2.