Question

By adding a small amount of KMnO₄ to concentrated H₂SO₄, a green oily compound is obtained, which is highly explosive in nature. Identify the compound from the following options.

• A. MnO₂
• B. MnSO₄
• C. Mn₂O₃
• D. Mn₂O₇

Answer 1

The correct option is D

Mn₂O₇

Answer: Option (D).

The explanation for the correct option.

1. ${\mathrm{KMnO}}_4$ is the strong oxidizing agent.
2. When a small amount of ${\mathrm{KMnO}}_4$ is treated with H₂SO₄, then Mn₂O₇ is formed.

$$\begin{gathered} 2{\mathrm{KMnO}}_4\left(\mathrm{s}\right)+2{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to 2{\mathrm{KHSO}}_4\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)+{\mathrm{Mn}}_2{\mathrm{O}}_7\left(\mathrm{aq}\right) \\ \mathrm{Poatassium}\mathrm{Sulphuric}\mathrm{Potassium}\mathrm{Water}\mathrm{Mangenese} \\ \mathrm{Permagnet}\mathrm{Acid}\mathrm{Hydrogen}\mathrm{heptoxide} \\ \mathrm{Sulphate} \end{gathered}$$

3.${\mathrm{Mn}}_2{\mathrm{O}}_7$ is a green-coloured volatile compound which is explosive in nature.

4. ${\mathrm{Mn}}_2{\mathrm{O}}_7$ becomes explosive in nature at 55^oC or above.

The explanation for the incorrect option.

• The reaction of ${\mathrm{KMnO}}_4$ with ${\mathrm{H}}_2{\mathrm{SO}}_4$ leads to the formation of ${\mathrm{Mn}}_2{\mathrm{O}}_7$_. It does not form ${\mathrm{MnO}}_2$, ${\mathrm{MnSO}}_4$ and ${\mathrm{Mn}}_2{\mathrm{O}}_4$_.
• Hence, these are incorrect options.

Therefore, Option (D) is correct.