A : pH of water termperature dependent.
R : Boiling water has pH less than 7.

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

### Step 1: Understand the Assertion
**Assertion (A):** The pH of water is temperature dependent.

- **Explanation:** The pH of water changes with temperature because the ionization of water (the dissociation into H⁺ and OH⁻ ions) is influenced by thermal energy. As temperature increases, the thermal energy of water molecules also increases, leading to more vibrations. This increased vibration weakens the bonds in the water molecules, resulting in a higher degree of ionization (more H⁺ and OH⁻ ions). Therefore, the pH of water decreases as temperature increases.

### Step 2: Understand the Reason
**Reason (R):** Boiling water has a pH less than 7.

- **Explanation:** At 25°C, pure water has a pH of 7. However, as the temperature increases, the pH of water decreases. For boiling water (100°C), the pH is approximately 6.14, which is indeed less than 7. This is because the concentration of H⁺ ions increases with temperature, leading to a lower pH.

### Step 3: Analyze the Relationship Between A and R
- Both the assertion and the reason are true. However, the reason provided does not correctly explain the assertion. The assertion is about the general temperature dependence of pH, while the reason specifically mentions boiling water. The relationship between temperature and pH is broader than just the boiling point.

### Conclusion
Both statements are true, but the reason does not correctly explain the assertion. Therefore, the correct answer is:

**Option 2:** Both are true, but the reason is not the correct explanation.

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