How many $mL$ of $1 \, M$ $H_2SO_4$ is required to neutralize $10 \, mL$ of $1 \, M$ $NaOH$ solution?

$x \ mg$ of pure $HCl$ was used to make an aqueous solution. $25.0 \ mL$ of $0.1 \ M$ $Ba(OH)_2$ solution is used when the $HCl$ solution was titrated against it. The numerical value of $x$ is . . . . . . $\times 10^{-1}$. (Nearest integer)
Given: Molar mass of $HCl$ and $Ba(OH)_2$ are $36.5$ and $171.0 \ g \ mol^{-1}$ respectively.

When oxygen is heated in the presence of a catalyst,$15 \%$ of it is converted into ozone. How many grams of oxygen are required to produce $33.6 \, L$ of $O_3$ at $STP$?

$A$ metal chloride contains $71\%$ chlorine by mass and has a vapor density of $50$. What is the atomic mass of the metal?

$5 \ g$ of zinc is treated separately with an excess of
$(a)$ dilute hydrochloric acid and
$(b)$ aqueous sodium hydroxide.
The ratio of the volumes of $H_{2}$ evolved in these two reactions is:

$40 \ mL$ of $0.1 \ N$ $KMnO_4$ is equivalent to $30 \ mL$ of $KHC_2O_4$ solution. How many $mL$ of $0.1 \ N$ $KOH$ are required to titrate $60 \ mL$ of the same $KHC_2O_4$ solution?