What is the dissociation constant of water at $25^{\circ}C$?

Which equation represents the calculation of the ionic product for distilled water?

At $298 \, K$,the equivalent conductivity of a $0.01 \, M$ solution of aniline hydrochloride is $122.5 \, \Omega^{-1} \, cm^2 \, eq^{-1}$,but in the presence of a sufficient excess of aniline to prevent hydrolysis,it is $106.5 \, \Omega^{-1} \, cm^2 \, eq^{-1}$. The equivalent conductivity of $HCl$ at infinite dilution is $426.0 \, \Omega^{-1} \, cm^2 \, eq^{-1}$. The hydrolysis constant of aniline is:

The $[OH^{-}]$ in a solution is $1 \times 10^{-12} \ mol \ dm^{-3}$. What is the concentration of $H^{+}$ ions?

Calculate $[OH^{-}]$ and $pH$ of a solution containing $[H^{+}] = 0.001 \ M$.

The $pH$ of water is $7$ at $25^{\circ} C$. If water is heated to $80^{\circ} C$,its $pH$ will: