Question

Potassium permanganate is a powerful oxidizing agent. In acidic solutions, the permanganate anion turns into Mn ⁽²⁺⁾ cation, while in basic solution, it becomes a solid MnO₂. How many electrons are involved in these processes, respectively?

1) 6, 2
2) 6, 3
3) 4, 5
4) 5, 3

Answer 1

In acidic solutions, the reduction of permanganate involves the transfer of 5 electrons to form Mn^2+. In basic solutions, the reduction involves the transfer of 2 electrons to form solid MnO2.

Step-by-step explanation:

In acidic solutions, the permanganate anion (MnO4^-) is reduced to the Mn2+ cation. This involves a transfer of 5 electrons:

MnO4^- + 8H+ + 5e- → Mn2+ + 4H2O

In basic solutions, the permanganate anion (MnO4^-) is reduced to solid MnO2. This reduction involves the transfer of 2 electrons:

MnO4^- + 4H2O + 2e- → MnO2 + 4OH-