Question

Which of the following is correct for pure water?

• A. $pH$ increases while $pOH$ decreases with temperature
• B. $pH$ decreases while $pOH$ increases with temperature
• C. Both $pH$ and $pOH$ decrease with rise in temperature
• D. Both $pH$ and $pOH$ increase with rise in temperature

Answer 1

The correct option is C Both $pH$ and $pOH$ decrease with rise in temperature

$pH=-log\left[H^{+}\right]$

Also for water,

$\left[H^{+}\right]\left[O{H}^{-}\right]={10}^{-14}$

$pH+pOH=14$

As we increase temperature, number of ions will increase and both $pH$ and $pOH$ will decrease with rise in temperature.