Assertion (A) : The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction
Reason (R) : The oxygen of peroxide is in `-1` oxidation state and it is converted to zero oxidation state in `O_(2)` and `-2` oxidation state in `H_(2)O`.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. Both A and R are false

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the decomposition of hydrogen peroxide (H₂O₂) to form water (H₂O) and oxygen (O₂) is an example of a disproportionation reaction.
- A disproportionation reaction is one in which the same species is both oxidized and reduced.

2. **Identifying the Reaction**:
- The decomposition reaction can be written as:
\[ 2 H_2O_2 \rightarrow 2 H_2O + O_2 \]
- Here, hydrogen peroxide decomposes into water and oxygen.

3. **Assigning Oxidation States**:
- In hydrogen peroxide (H₂O₂):
- The oxidation state of hydrogen (H) is +1.
- The oxidation state of oxygen (O) in H₂O₂ is -1 (since it is a peroxide).
- In water (H₂O):
- The oxidation state of hydrogen (H) is +1.
- The oxidation state of oxygen (O) is -2.
- In molecular oxygen (O₂):
- The oxidation state of oxygen (O) is 0 (elemental form).

4. **Analyzing Changes in Oxidation States**:
- The oxygen in H₂O₂ changes from -1 to:
- -2 in H₂O (reduction)
- 0 in O₂ (oxidation)
- Thus, one part of the oxygen is reduced (gaining electrons) and another part is oxidized (losing electrons).

5. **Conclusion on Disproportionation**:
- Since the same element (oxygen) is undergoing both oxidation and reduction in the reaction, it qualifies as a disproportionation reaction.
- Therefore, the assertion is true.

6. **Understanding the Reason**:
- The reason states that the oxygen in hydrogen peroxide is in the -1 oxidation state and it is converted to 0 in O₂ and -2 in H₂O.
- This statement is accurate as we have established the oxidation states correctly.

7. **Final Evaluation**:
- Both the assertion and the reason are true.
- The reason correctly explains the assertion.

### Final Answer:
Both the assertion (A) and the reason (R) are true, and the reason is the correct explanation for the assertion. Therefore, the answer is **1**.