A : Aq solution of washing soda is alkaline in nature
R : It is salt of weak acid and strong base.

Options

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

Answer

To solve the assertion and reasoning question, we need to analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion (A):** An aqueous solution of washing soda is alkaline in nature.

- **Explanation:** Washing soda is chemically known as sodium carbonate (Na2CO3). When dissolved in water, it dissociates into sodium ions (Na⁺) and carbonate ions (CO3²⁻). The carbonate ions can react with water (hydrolyze) to form bicarbonate (HCO3⁻) and hydroxide ions (OH⁻), which increases the pH of the solution, making it alkaline.

### Step 2: Analyze the Reason
**Reason (R):** It is a salt of weak acid and strong base.

- **Explanation:** Sodium carbonate is indeed a salt formed from the reaction of a weak acid (carbonic acid, H2CO3) and a strong base (sodium hydroxide, NaOH). The presence of the strong base (NaOH) contributes to the basicity of the solution, while the weak acid (H2CO3) does not fully dissociate, allowing the solution to maintain a higher pH.

### Step 3: Conclusion
- Both the assertion and the reason are correct.
- The reason correctly explains the assertion because the alkaline nature of the solution is due to the presence of a strong base (from the salt of a weak acid and strong base).

### Final Answer
Both assertion (A) and reason (R) are correct, and the reason correctly explains the assertion.