A : Dissolution of concentrated `H_(2)SO_(4)` in water is highly exothermic process .
R : Sulphuric acid is always diluted by adding acid to water slowly .

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 explanation of the assertion , then mark (2)
C. If Assertion is true statement but Reason is false , then mark (3)
D. If both Assertion and Reason are false statements , then mark (4)

Answer

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

**Assertion (A):** The dissolution of concentrated \( H_2SO_4 \) in water is a highly exothermic process.

**Reason (R):** Sulfuric acid is always diluted by adding acid to water slowly.

### Step-by-step Solution:

1. **Evaluate the Assertion (A):**
- The dissolution of concentrated sulfuric acid (\( H_2SO_4 \)) in water is indeed a highly exothermic process. When concentrated sulfuric acid is mixed with water, it releases a significant amount of heat. This is due to the strong interactions between the acid and water molecules, leading to the dissociation of sulfuric acid into ions and the release of energy.
- **Conclusion:** Assertion (A) is **True**.

2. **Evaluate the Reason (R):**
- The reason states that sulfuric acid is always diluted by adding acid to water slowly. This is a safety precaution. When sulfuric acid is added to water, the heat released can cause the solution to boil and splash, which can be dangerous. Therefore, it is recommended to add acid to water slowly to control the heat released and prevent accidents.
- **Conclusion:** Reason (R) is **True**.

3. **Determine the Relationship Between A and R:**
- Although both the assertion and reason are true, the reason does not explain why the dissolution of concentrated \( H_2SO_4 \) in water is highly exothermic. The reason provides a safety guideline rather than an explanation of the exothermic nature of the process.
- **Conclusion:** The reason is not the correct explanation of the assertion.

4. **Select the Correct Option:**
- Based on the evaluations:
- Option 1 states that both A and R are true and R is the correct explanation of A (this is incorrect).
- Option 2 states that both A and R are true but R is not the correct explanation of A (this is correct).
- Option 3 states that A is true but R is false (this is incorrect).
- Option 4 states that both A and R are false (this is incorrect).
- Therefore, the correct answer is **Option 2**.

### Final Answer:
**Option 2: Both assertion and reason are true, but reason is not the correct explanation of assertion.**

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