The number of $H^{+}$ ions present in $10 \ mL$ of a solution with $pH = 12$ is ........

$A$ beer has a $pH$ of $4.30$. What is the $[H_3O^{+}]$ concentration?

The value of the ionic product of water $(K_w)$ at $393 \ K$ is:

$100 \ mL$ of $NaOH$ solution has a $pH = 10$. Calculate the concentration of hydroxide ions,$[OH^{-}]$.

At $90\,^oC$,pure water has $[H^{+}] = 10^{-6}\,M$. If $100\, mL$ of $0.2\, M\, HCl$ is added to $200\, mL$ of $0.1\, M\, KOH$ at $90\,^oC$,then the $pH$ of the resulting solution will be:

Find the concentration of hydrogen ions in a solution with $pH = 5.4$ in $mol/L$.