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 $90 \, ^\circ C$?

At $30\,^{\circ}C$ temperature,what is the ratio of the dissociation constant of water $(K_a)$ to the ionic product of water $(K_w)$?

At $90\,^{\circ}C$,pure water has $H_3O^{+}$ ion concentration of $10^{-6}\,mol\,L^{-1}$. The $K_w$ at $90\,^{\circ}C$ is

The $pH$ of an aqueous solution having hydroxide ion concentration as $1 \times 10^{-5} \ M$ is

Write about the relation of $pH$ and the concentration of $H_3O^+$ and $OH^-$ in acidic,basic,and neutral solutions.

$2$. Given below are two statements:
Statement $I$: The changes in $pH$ with temperature are so small that we often ignore them.
Statement $II$: When the hydrogen ion concentration changes by a factor of $100$,the $pH$ changes by one unit.
In the light of the above statements,identify the correct answer from the options given below: