Q16 / 75 · JEE Main 2020 (08 Jan Shift 2) · Chemistry

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
    Both assertion and reason are true, and the reason is the correct explanation for the assertion.
  • Correct answer
    B
    Both assertion and reason are false.
  • C
    Both assertion and reason are true, but the reason is not the correct explanation for the assertion.
  • D
    Assertion is not true, but reason is true.

Solution

H2O(l)⇌H(aq)++OH(aq)−

For ionization of H 2 O:ΔH>O ⇒  Endothermic on temperature increase reaction shifts forward

⇒ both H + and H - increase

⇒ pH & pOH decreases.

Hence, the correct answer is option: 'B'.

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