If the $pH$ of an aqueous solution is $6$,then its $pOH$ is:

Three acidic solutions $A, B$ and $C$ have $pH = 0, 3$ and $5$ respectively.
$(i)$ Which solution has the highest concentration of $H^{+}$ ions?
$(ii)$ Which solution has the lowest concentration of $H^{+}$ ions?

In a basic aqueous solution,if the concentration of $[OH^-]$ decreases,what happens to the $pOH$?

$(i)$ What is the $pH$ range for a base?
$(ii)$ How can the strength of a basic solution be increased?

What is the concentration of $[H_3O^+]$ in distilled water at $298 \; K$?

What is the concentration of $[OH^-]$ in distilled water at $298 \; K$?