How many moles of potassium chlorate $(KClO_3)$ are required to be heated to produce $11.2 \text{ L}$ of oxygen gas at $STP$?

$KMnO_4$ reacts with oxalic acid according to the equation:
$2MnO_4^- + 5C_2O_4^{2-} + 16H^+ \to 2Mn^{2+} + 10CO_2 + 8H_2O$
Here,$20 \ mL$ of $0.1 \ M$ $KMnO_4$ is equivalent to:

What is the weight of $50\%$ pure $HCl$ required to react completely with $100 \ g$ of $100\%$ pure limestone $(CaCO_3)$ (in $g$)?

The volume occupied by $4.4 \ g$ of $CO_2$ at $STP$ is ............... $L$.

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 $g$)?

$A$ $250 \, mL$ solution of sodium carbonate contains $5.3 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is taken and diluted with distilled water to $0.1 \, L$,what will be the concentration of the resulting solution?