Question

The ionic product of water _____ with the increase in temperature

• A. decreases
• B. increases
• C. remains constant
• D. None of the above

Answer 1

Answer: (B)

Water is dissociated into hydrogen and hydroxyl ions, as represented by equation
$H_{2}O\rightleftharpoons H^{+}+O{H}^{-}$
$K=\frac{\left[H^{+}\right]\left[O{H}^{-}\right]}{\left[H_{2}O\right]}$
$K\left[H_{2}O\right]=\left[H^{+}\right]\left[O{H}^{-}\right]$
$K_w=\left[H^{+}\right]\left[O{H}^{-}\right]$
where, $K_w$ is ionic product of water.
At $25^{\circ }C,K_w=1\times 10^{-14}$
The value of ionic product of water increases on increasing the temperature, because the degree of ionisation increases, on increasing the temperature.

Temp${/}^{\circ }C$	$K_w$
25	$1\times 10^{-14}$
60	$9.6\times 10^{-14}$
100	$5.5\times 10^{-13}$