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

The concentration of hydrogen ion in a sample of soft drink is $3.8 \times 10^{-3} \ M$. What is its $pH$ (in $.42$)?

The $pH$ of pure water at $80^{\circ} C$ 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:

Hydrogen ion concentration in $mol/L$ in a solution of $pH = 5.4$ will be

Calculate the concentration of $H_3O^{+}$ ion if the $pH$ of the solution is $2.8$.