$1.25 \ g$ of a solid dibasic acid is completely neutralized by $25 \ mL$ of $0.25 \ M$ $Ba(OH)_2$ solution. The molecular mass of the acid is:

What fraction of $Fe$ exists as $Fe(III)$ in $Fe_{0.96}O$?
(Consider $Fe_{0.96}$ to be made up of $Fe(II)$ and $Fe(III)$ only)

Chlorine is prepared in the laboratory by treating manganese dioxide $(MnO_{2})$ with aqueous hydrochloric acid according to the reaction
$4HCl_{(aq)} + MnO_{2(s)} \rightarrow 2H_{2}O_{(l)} + MnCl_{2(aq)} + Cl_{2(g)}$
How many grams of $HCl$ react with $5.0\ g$ of manganese dioxide?

What will be the amount of $MgCl_2$ (in $g$) when $17 \ g$ of $HCl$ is reacted with an excess of $MgO$ in the following reaction: $MgO + 2HCl \to MgCl_2 + H_2O$?

$A$ mixture of $H_2$ and $O_2$ at $1 \, atm$ pressure contains $20 \%$ by weight of $H_2$. Find out the partial pressure of $H_2$ in $atm$.

When $10 \ g$ of $90 \%$ pure limestone is heated, the approximate volume $($in $L$ $)$ of $CO_2$ liberated at $\text{STP}$ is: