Question

Acidified potassium dichromate reacts with potassium iodide and oxidises it to $I_2$. What is the oxidation state of chromium in the products of the reaction?

• A. $+4$
• B. $+6$
• C. $+3$
• D. $+2$

Answer 1

Answer: (C)

$+3$

Answer 2

During the reaction $K_2Cr_2O_7$ is converted to $Cr_2(SO_4)_3$ ${K2Cr2O7 + 7H2SO4 + 6KI -> 4K2SO4 + Cr2(SO4)3 \+ 7H2O + 3I2}$ In $Cr_2(SO_4)_3$, $O.S.$ of $Cr$ is $+3$.