Question

The dark purple colour of $KMnO_4$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

• A. 5
• B. 1
• C. 7
• D. 2

Answer 1

Answer: (A)

5

Answer 2

$2K\overset{+7}{Mn}O_4 + 5H_2C_2O_4 + 3H_2SO_4 → K_2SO_4 + 2\overset{+2}{Mn}SO_4 + 10CO_2 + 8H_2O$
Change in oxidation state of Mn is 5.

So, the correct option is (A): 5