$29.2 \% (w/w)$ $HCl$ stock solution has a density of $1.25 \ g \ mL^{-1}$. The molecular weight of $HCl$ is $36.5 \ g \ mol^{-1}$. The volume $(mL)$ of stock solution required to prepare a $200 \ mL$ solution of $0.4 \ M$ $HCl$ is :

What volume of $O_{2(g)}$ measured at standard condition will be formed by the action of $100 \ mL$ of $0.5 \ N \ KMnO_4$ on hydrogen peroxide in an acidic solution? The skeleton equation for the reaction is:
$KMnO_4 + H_2SO_4 + H_2O_2 \to KHSO_4 + MnSO_4 + O_2 + H_2O$
(Answer in $L$)

How many moles of $H_2O_2$ are required to decolorize $1$ mole of $KMnO_4$ (in $.5$)?

How many grams of $60\% \, H_2SO_4$ are required for the complete reaction of $100 \, g \, CaCO_3$?

What is the weight (in $g$) of $Na_2CO_3$ (molar mass $= 106$) present in $250 \ mL$ of its $0.2 \ M$ solution?

What quantity of oxygen is required for complete burning of $15.6 \ g$ benzene (in $g$)?