Write the ionic equations for the oxidising action of potassium permanganate for its reaction with $I^-$ in both acidic and alkaline solutions.

Question

Statement-I : Consider the following pairs of ions $(\text{Sc}^{3+}, \text{Ti}^{3+}), (\text{Ti}^{4+}, \text{Ni}^{2+}), (\text{Cu}^{2+}, \text{Zn}^{2+})$ and $(\text{Cr}^{3+}, \text{Mn}^{3+})$. Out of these pairs three pairs consist of ions that are both coloured :
Statement-II : Among the lanthanide ions $\text{Eu}^{2+}$, $\text{Gd}^{3+}$, $\text{Ce}^{4+}$ and $\text{Tb}^{4+}$, the ion $\text{Tb}^{4+}$ is the strongest reducing agent.
Choose the correct option.

Answer 1

Write the ionic equations for the oxidising action of potassium permanganate for its reaction with $I^-$ in both acidic and alkaline solutions.
Solution:
Potassium permanganate ($ KMnO_4 $) acts as an oxidizing agent in both acidic and alkaline solutions. It is reduced to $ Mn^{2+} $ in acidic solution and $ MnO_2 $ in alkaline solution. The reaction with iodide ions ($ I^- $) involves the oxidation of iodide to iodine ($ I_2 $).
1. In Acidic Solution:
In an acidic medium, $ KMnO_4 $ is reduced to $ Mn^{2+} $, and iodide ions ($ I^- $) are oxidized to iodine ($ I_2 $). The ionic equation in acidic solution is:
\[ 2MnO_4^- + 16H^+ + 10I^- \rightarrow 2Mn^{2+} + 5I_2 + 8H_2O \] This equation represents the reduction of permanganate to manganese(II) and the oxidation of iodide to iodine in an acidic medium.
2. In Alkaline Solution:
In an alkaline medium, $ KMnO_4 $ is reduced to $ MnO_2 $ (manganese dioxide), and iodide ions ($ I^- $) are oxidized to iodine ($ I_2 $). The ionic equation in alkaline solution is:
\[ 2MnO_4^- + 2H_2O + 10I^- \rightarrow 2MnO_2 + 5I_2 + 4OH^- \] This equation represents the reduction of permanganate to manganese dioxide and the oxidation of iodide to iodine in an alkaline medium.
In summary, potassium permanganate behaves as an oxidizing agent in both acidic and alkaline solutions, with the following outcomes:
- In acidic medium: $ KMnO_4 $ is reduced to $ Mn^{2+} $, and $ I^- $ is oxidized to $ I_2 $.
- In alkaline medium: $ KMnO_4 $ is reduced to $ MnO_2 $, and $ I^- $ is oxidized to $ I_2 $.

Write the ionic equations for the oxidising action of potassium permanganate for its reaction with \(I^-\) in both acidic and alkaline solutions.

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Solution and Explanation

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