At $25^{\circ}C$,if $[OH^{-}] = 10^{-9} \ M$,find the $pH$ value of the solution.

Pure water is kept in a vessel and it remains exposed to atmospheric $CO_2$ which is absorbed,then its $pH$ will be

The $pH$ of milk,black coffee,tomato juice,lemon juice and egg white are $6.8, 5.0, 4.2, 2.2$ and $7.8$ respectively. Calculate the corresponding hydrogen ion concentration $[H^+]$ in each.

The $pH$ of pure water at $80^{\circ} C$ is

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 $OH^{-}$ is an exothermic reaction.

The unit of the ionic product of water $(K_W)$ is.......