Question

On addition of small amount of \(KMnO_4\) to concentrated \(H_2SO_4\), a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.

• A. \(\mathrm{Mn_2O_7}\)
• B. \(\mathrm{MnO_2}\)
• C. \(\mathrm{MnSO_4}\)
• D. \(\mathrm{Mn_2O_3}\)

Hint:

\[ \mathrm{Mn_2O_7} \] is manganese heptoxide: \[ \text{a dark green explosive liquid} \]

Answer 1

The Correct Option is A

Step 1: Recall the reaction of \(KMnO_4\) with concentrated \(H_2SO_4\).
When: \[ KMnO_4 \] reacts with concentrated: \[ H_2SO_4 \] a dark green oily liquid is formed: \[ \mathrm{Mn_2O_7} \] Reaction: \[ 2KMnO_4+2H_2SO_4 \rightarrow K_2SO_4+2HMnO_4 \] \[ 2HMnO_4 \rightarrow Mn_2O_7+H_2O \]

Step 2: Identify the explosive compound.
\[ \mathrm{Mn_2O_7} \] is highly unstable and explosive. Thus the green oily liquid obtained is: \[ \mathrm{Mn_2O_7} \]

Step 3: Identify the correct option.
Therefore: \[ \boxed{ \mathrm{ (A)\ Mn_2O_7 } } \]