When sodium chloride is dissolved in water,the sodium ion undergoes ........

The $pH$ of a solution is $5.0$. To this solution,sufficient acid is added to decrease the $pH$ to $2.0$. The increase in hydrogen ion concentration is $...$ times.

The definition of $pH$ is

What is the $pH$ of the solution containing $1.342 \times 10^{-3} \ M \ H^{+}$ ions?
$(\log 1.342 = 0.1277)$

What is the concentration of $H_3O^{+}$ ions in a solution having $pOH$ value $9$?

$pH$ of a solution is $5$. Its hydroxyl ion concentration is