Calculate the concentration of $H^{+}$ ions in a solution if $pOH$ is $11$.

An alcoholic drink has a $pH = 4.7$. What is the $OH^{-}$ ion concentration of this solution? (Given: $K_w = 10^{-14} \ mol^2/L^2$)

The $pH$ of pure water or neutral solution at $50\,^{\circ}C$ is .... ($pK_w = 13.26$ at $50\,^{\circ}C$)

If the $pH$ of a solution increases from $3$ to $6$,then its $H^{+}$ ion concentration:

Observe the following solutions:
$I$. Black coffee
$II$. $0.2 \ M \ NaOH$
$III$. Lemon juice
$IV$. Lime water
$V$. Human saliva
$VI$. Tomato juice
The number of solutions having $pH$ range of $1-7$ and $7-14$,in the above list,is respectively.

If $[H_3O^+]$ of a solution is $1 \times 10^{-4} \text{ M}$, what is the value of $pOH$ at $298 \text{ K}$?