(A): `OX^(-)` on heating in the presence of `OH^(-)` gives `X^(-)` and `XO_(3)^(-)`
(R): Conversion of `OX^(-)` to `X^(-)` and `XO_(3)^(-)`, is called disproportionation.

Options

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

Answer

To solve the question, we need to analyze both the assertion (A) and the reasoning (R) provided.

### Step 1: Understanding the Assertion (A)
The assertion states that when `OX^(-)` is heated in the presence of `OH^(-)`, it produces `X^(-)` and `XO3^(-)`.

- **Analysis**: This reaction involves the conversion of a compound `OX^(-)` into two different products: `X^(-)` and `XO3^(-)`.

### Step 2: Understanding the Reasoning (R)
The reasoning states that the conversion of `OX^(-)` to `X^(-)` and `XO3^(-)` is called disproportionation.

- **Analysis**: Disproportionation is a specific type of redox reaction where a single substance is simultaneously oxidized and reduced, resulting in two different products with different oxidation states. In this case, `X` in `OX^(-)` is being converted into two different oxidation states: `X^(-)` (which is reduced) and `XO3^(-)` (which is oxidized).

### Step 3: Conclusion
Both the assertion and reasoning are true. The reaction described in the assertion indeed occurs, and the process by which `OX^(-)` is converted into `X^(-)` and `XO3^(-)` is correctly identified as disproportionation.

### Final Answer
Both assertion (A) and reasoning (R) are true.