Question

At ${50}^{\circ }C$, $pH+pOH$ is:

• A. less than $14$
• B. more than $14$
• C. equal to $14$
• D. equal to $4$

Answer 1

The correct option is A less than $14$

At ${25}^{0}C$,

$pH+pOH$ is $14$.

At ${50}^{0}C$, dissociation of water molecules will increase ($k_w$ increases with temperature), resulting in higher $\left[H^{+}\right]$ and $\left[O{H}^{-}\right]$.

So both $pH$ and $pOH$ will be less than the value at ${25}^{0}C$.