Observe the following solutions:
$I$. Black coffee
$II$. $0.2 \ M \ NaOH$
$III$. Lemon juice
$IV$. Lime water
$V$. Human Saliva
$VI$. Tomato juice
The number of solutions with $pH$ less than $7$ is

$2$. 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:

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

Ionic product of water at $310 \, K$ is $2.7 \times 10^{-14}$. What is the $pH$ of neutral water at this temperature?

At $90\,^{\circ}C$ pure water has $[H_3O^{+}] = 10^{-6}\,M$. The value of $K_w$ at this temperature will be:

The $pH$ of $1 \ N \ H_2O$ is