If a solution has $pOH$ value $12$ at $25\,^{\circ}C$,$H^{+}$ concentration should be

The $pH$ of a sample of vinegar is $3.76$. Calculate the concentration of hydrogen ion in it in $mol \ dm^{-3}$?

An aqueous solution of $HCl$ has a $pH$ of $2.0$. When water is added to increase the $pH$ to $5.0$,the hydrogen ion concentration

The concentration of hydrogen ion in pure water at $298 \ K$ is:

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.

At $90 \, ^\circ C$,the concentration of $[H_3O^+]$ in pure water is $10^{-6} \, mol \, L^{-1}$. What is the value of $K_W$ at $90 \, ^\circ C$?