What is the concentration of hydrogen $[H^{+}]$ ions in $0.01 \, M \, HCl$?

$600 \, mL$ of $0.01 \, M \, HCl$ is mixed with $400 \, mL$ of $0.01 \, M \, H_2SO_4$. The $pH$ of the mixture is $....... \times 10^{-2}$. (Nearest integer) [Given $\log 2 = 0.30, \quad \log 3 = 0.48, \quad \log 5 = 0.69, \quad \log 7 = 0.84, \quad \log 11 = 1.04$]

$NaOH$ is a strong base. What will be the $pH$ of a $5.0 \times 10^{-2} \ M$ $NaOH$ solution? (Given: $\log \ 2 = 0.3$)

$10^{-6} \ M \ NaOH$ is diluted $100$ times. The $pH$ of the diluted base is

Find the number of equivalents of $HBr$ present in $100 \ mL$ of its solution whose $pH$ is $4$.

The $pH$ of $100 \ mL$ of an aqueous solution of a strong acid is $1$. The volume of water to be added to change its $pH$ to $2$ is .......... $mL$.