A : Increasing the temperature , increases `[H^+]` concentration in water
R: Water is acidic at higher temperature

Options

A. If both Assertion & Reason are true and the reason in the corret explanation of the assertion, then mark
B. If both assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark
C. If Assertion is true statement but Reason is false then mark
D. If both Assertion and Reason are false statements , then mark

Answer

To solve the question regarding the assertion and reasoning about the behavior of water with temperature changes, we will follow a step-by-step approach.

### Step 1: Analyze the Assertion
The assertion states that "Increasing the temperature increases [H⁺] concentration in water."

- **Explanation**: When water (H₂O) dissociates, it produces H⁺ ions and OH⁻ ions. The dissociation of water can be represented as:
\[ H_2O \rightleftharpoons H^+ + OH^- \]
This reaction is endothermic, meaning it absorbs heat. According to Le Chatelier's principle, if we increase the temperature, the equilibrium will shift to favor the endothermic reaction to absorb the added heat. Therefore, increasing the temperature will indeed increase the concentration of H⁺ ions.

### Step 2: Analyze the Reason
The reason states that "Water is acidic at higher temperature."

- **Explanation**: For water to be considered acidic, the concentration of H⁺ ions must be greater than that of OH⁻ ions, resulting in a pH less than 7. However, when the temperature of pure water increases, both [H⁺] and [OH⁻] concentrations increase equally because they are produced in a 1:1 ratio from the dissociation of water. Therefore, the pH remains neutral (around 7) at higher temperatures, as both ions increase proportionally.

### Step 3: Conclusion
- The assertion is **true** because increasing temperature does increase the concentration of H⁺ ions.
- The reason is **false** because water does not become acidic at higher temperatures; it remains neutral.

### Final Answer
Since the assertion is true and the reason is false, the correct option is option 3: "Assertion is true, but reason is false."

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