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For the following Assertion and Reason t...

For the following Assertion and Reason the correct option is:
Assertion :The pH of water increases with increase in temperature
Reason : The dissociation of water into `H^(+)` and `OH^(-)` is an exothermic reaction

A

Assertion is not true, but reason is true

B

Both assertion and reason are true, but the reason is not the correct explanation for the

C

Both assertion and reason are false

D

Both assertion and reason are true, and the reason the correct explanation for the assertion

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the assertion and reason provided, we will analyze both statements step by step. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "The pH of water increases with an increase in temperature." - Normally, pure water has a pH of 7 at 25°C. As the temperature increases, the dissociation of water into hydrogen ions (H⁺) and hydroxide ions (OH⁻) occurs more readily. 2. **Effect of Temperature on Water Dissociation**: - The dissociation of water can be represented by the equation: \[ H_2O \rightleftharpoons H^+ + OH^- \] - As temperature increases, the equilibrium shifts to the right, leading to an increase in the concentration of H⁺ ions. 3. **Calculating pH**: - pH is calculated using the formula: \[ \text{pH} = -\log[H^+] \] - If the concentration of H⁺ ions increases, the pH value will actually decrease (not increase). 4. **Understanding the Reason**: - The reason states that "The dissociation of water into H⁺ and OH⁻ is an exothermic reaction." - This statement is incorrect. The dissociation of water is an endothermic process, meaning it absorbs heat. When heat is added, the reaction shifts to produce more H⁺ and OH⁻ ions. 5. **Conclusion**: - The assertion is false because the pH of water actually decreases with an increase in temperature (it becomes more acidic). - The reason is also false because the dissociation of water is an endothermic reaction, not exothermic. ### Final Answer: Both the assertion and the reason are false.
To solve the question regarding the assertion and reason provided, we will analyze both statements step by step. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "The pH of water increases with an increase in temperature." - Normally, pure water has a pH of 7 at 25°C. As the temperature increases, the dissociation of water into hydrogen ions (H⁺) and hydroxide ions (OH⁻) occurs more readily. ...
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