Question

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 $O{H}^{-}$ an exothermic reaction.

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

Answer 1

The correct option is A Both assertion and reason are false.

$H_{2}O\to H^{+}+O{H}^{-}$ is an endothermic process.

On increasing the temperature, the value of $K_w$ increases which will result in decrease in $p{K}_w$. So we can say that $pH$ of water will decrease on increasing temperature because $pH$ for water $=\frac{1}{2}p{K}_w.$