Q. The ionic product of water _____ with the increase in temperature
AMUAMU 2003
Solution:
Water is dissociated into hydrogen and hydroxyl ions, as represented by equation
$H _{2} O \rightleftharpoons H ^{+}+ OH ^{-} $
$K =\frac{\left[ H ^{+}\right]\left[ OH ^{-}\right]}{\left[ H _{2} O \right]} $
$K\left[ H _{2} O \right] =\left[ H ^{+}\right]\left[ OH ^{-}\right]$
$K_{w} =\left[ H ^{+}\right]\left[ OH ^{-}\right]$
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
$5.5 \times 10^{-13}$
| Temp$/^{\circ}C$ | $K_w$ |
|---|---|
| 25 | $1\times 10^{-14}$ |
| 60 | $9.6 \times 10^{-14}$ |
| 100 | $5.5 \times 10^{-13}$ |