$A$ metal exists as an oxide with formula $M_{0.96} O$. Metal $M$ can exist as $M^{2+}$ and $M^{3+}$ in its oxide $M_{0.96} O$. The percentage of $M^{3+}$ in the oxide is nearly: (in $\%$)

The solution of sulphuric acid contains $80\%$ by weight $H_2SO_4$. The specific gravity of this solution is $1.71$. Its normality is about:

$20 \, mL$ of $1 \, N \, KMnO_4$ solution reacts with $20 \, mL$ of oxalic acid solution. The weight of oxalic acid crystals $(H_2C_2O_4 \cdot 2H_2O)$ in the $1 \, N$ solution is . . . . . . $g$.

If the density of $1 \ mol$ of a gas at $NTP$ is $0.1784 \ g/L$,what is the weight of $1 \ mol$ of the gas in $g$?

In the laboratory,chlorine is prepared by the reaction of manganese dioxide $(MnO_2)$ with aqueous hydrochloric acid $(HCl)$ as follows:
$4HCl_{(aq)} + MnO_{2(s)} \to 2H_2O_{(l)} + MnCl_{2(aq)} + Cl_{2(g)}$
How many grams of $HCl$ will react with $5.0 \ g$ of manganese dioxide (in $g$)?

$5 \ g$ 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: