If the value of the dissociation constant of water is $1.8 \times 10^{-16}$,what is the ionic product of water?

At $25 \, ^\circ C$,the ionic product of water $(K_w)$ is equal to .......

$pH$ scale was introduced by

$2$. 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:

As the temperature increases,the $pH$ of a $KOH$ solution

$pH$ of a soft drink is $3.6$. Calculate the concentration of hydrogen ions in it.