Q4.70P - Chemistry: Molecular Nature Of Matter And Change

Question

Give the oxidation number of manganese in the following:

$$\begin{gathered} \left(a\right)Mn{O}_4^{2-} \\ \left(b\right)M{n}_2{O}_3^{} \\ \left(c\right)KMn{O}_4 \end{gathered}$$

Step-by-Step Solution

Answer

You need to provide the oxidation no of manganese for the given compounds.

Step 1: Oxidation state of manganese in MnO 4 2-

Oxidation state of Oxygen is -2.

Let, oxidation state of manganese in MnO₄^2- is x.

No you can write,

  $$\begin{gathered} x+4\left(-2\right)=-2 \\ x=+6 \end{gathered}$$

Hence, oxidation state of manganese in MnO₄^2- is +6.

Step 2: Oxidation state of manganese in Mn 2 O 3

Oxidation state of Oxygen is -2.

Let, oxidation state of manganese in Mn₂O₃ is y.

No you can write,

  $$\begin{gathered} 2y+3\left(-2\right)=0 \\ 2y=+6 \\ y=+3 \end{gathered}$$

Hence, oxidation state of manganese in Mn₂O₃ is +3.

Step 3: Oxidation state of manganese in KMnO 4

Oxidation state of Potassium is +1.

Oxidation state of Oxygen is -2.

Let, oxidation state of manganese in KMnO₄ is z.

No you can write,

  $$\begin{gathered} \left(+1\right)+z+4\left(-2\right)=0 \\ z=+7 \end{gathered}$$

Hence, oxidation state of manganese in KMnO₄ is +7.