what is the oxidation number for chromium in each of these compounds. show your work. A. K2CrO4 B. Cr2O3

A. + 6.

B. + 3.

Explanation:

A. K₂CrO₄:

To calculate the oxidation no. of an element in a compound:

We have that the sum of the oxidation no. of different elements in the compound multiplied by its no. is equal to the overall charge of the compound.

∵ 2 (oxidation no. of K) + (oxidation no. of Cr) + 4 (oxidation no. of O) = 0.

oxidation no. of K = + 1, oxidation no. of O = - 2.

∴ 2 ( + 1) + (oxidation no. of Cr) + 4 ( - 2) = 0.

∴ 2 + (oxidation no. of Cr) - 8 = 0.

∴ (oxidation no. of Cr) - 6 = 0.

∴ oxidation no. of Cr = + 6.

B. Cr₂O₃:

∵ 2 (oxidation no. of Cr) + 3 (oxidation no. of O) = 0.

oxidation no. of O = - 2.

∴ 2 (oxidation no. of Cr) + 3 ( - 2) = 0.

∴ 2 (oxidation no. of Cr) - 6 = 0.

∴ 2 (oxidation no. of Cr) = + 6.

∴ (oxidation no. of Cr) = + 6/2 = + 3.