Q: What is the oxidation number of Manganese (Mn) in Potassium Permanganate ($KMnO4$)?

In $KMnO4$, let the oxidation state of Mn be $x$.\nOxidation state of $K = +1$\nOxidation state of $O = -2$ $+1 + x + 4(-2) = 0 \implies 1 + x - 8 = 0 \implies x = +7$.

Question 1

What is the oxidation number of Manganese (Mn) in Potassium Permanganate ($KMnO4$)?

Accepted Answer

In $KMnO4$, let the oxidation state of Mn be $x$.
Oxidation state of $K = +1$
Oxidation state of $O = -2$ $+1 + x + 4(-2) = 0 \implies 1 + x - 8 = 0 \implies x = +7$.

Question 2

In Hydrogen Peroxide ($H2O2$), the oxidation state of oxygen is:

Accepted Answer

In peroxides, oxygen has an oxidation state of $-1$ because two oxygen atoms are linked together by a single covalent bond.

Question 3

What is the oxidation number of Chromium (Cr) in $K2Cr2O7$?

Accepted Answer

Let the oxidation number of Cr be $x$. $2(+1) + 2x + 7(-2) = 0 \implies 2 + 2x - 14 = 0 \implies 2x = 12 \implies x = +6$.

Question 4

In which of the following compounds does oxygen exhibit a positive oxidation state?

Accepted Answer

Fluorine is more electronegative than oxygen. Therefore, in Oxygen Difluoride ($OF2$), oxygen exhibits an oxidation state of $+2$.

Question 5

Which of the following is an example of a disproportionation reaction?

Accepted Answer

In $2H2O2 \rightarrow 2H2O + O2$, oxygen in $H2O2$ (-1 state) is simultaneously oxidized to $O2$ (0 state) and reduced to $H2O$ (-2 state).

Redox Reactions