A : `H_2O` liberate `O_2` an reaction with `KMnO_4` in acidic medium.
R : `KMnO_4` oxidises `H_2O_2" to " O_2`.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanantion of the assertion, then mark (2)
C. If assertion is true statements but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the problem, we need to analyze the assertion (A) and the reason (R) given in the question.

### Step 1: Understanding the Assertion (A)
The assertion states that H₂O₂ liberates O₂ when it reacts with KMnO₄ in an acidic medium.

**Hint:** Recall the properties of hydrogen peroxide (H₂O₂) as a reducing agent and its behavior in acidic conditions.

### Step 2: Analyzing the Reaction
When H₂O₂ is mixed with KMnO₄ in an acidic medium (such as sulfuric acid), a redox reaction occurs. KMnO₄ acts as an oxidizing agent.

**Hint:** Remember that in redox reactions, one species is oxidized while the other is reduced.

### Step 3: Identifying Oxidation States
In KMnO₄, manganese (Mn) has an oxidation state of +7. In acidic medium, it gets reduced to Mn²⁺ (oxidation state +2).

**Hint:** Calculate the oxidation states to understand the changes occurring during the reaction.

### Step 4: Writing the Balanced Reaction
The balanced chemical reaction for the reaction between H₂O₂ and KMnO₄ in acidic medium is:
\[ 2 \text{KMnO}_4 + 5 \text{H}_2\text{O}_2 + 6 \text{H}_2\text{SO}_4 \rightarrow 2 \text{MnSO}_4 + 5 \text{O}_2 + 8 \text{H}_2\text{O} + K_2\text{SO}_4 \]

**Hint:** Ensure that the number of atoms of each element is the same on both sides of the equation.

### Step 5: Confirming the Assertion
From the balanced reaction, it is evident that H₂O₂ does indeed liberate O₂ when it reacts with KMnO₄ in acidic medium. Thus, the assertion is correct.

**Hint:** Look for the products formed in the reaction to confirm the assertion.

### Step 6: Understanding the Reason (R)
The reason states that KMnO₄ oxidizes H₂O₂ to O₂. This is indeed true, as KMnO₄ facilitates the oxidation of H₂O₂, leading to the liberation of O₂.

**Hint:** Identify the role of KMnO₄ in the reaction to understand its function as an oxidizing agent.

### Step 7: Conclusion
Both the assertion and the reason are correct, and the reason provided is the correct explanation of the assertion. Therefore, the answer to the question is that both A and R are true, and R is the correct explanation of A.

**Final Answer:** Both A and R are true, and R is the correct explanation of A.