$A$ given initial mass of $KClO_3$ on $50\%$ decomposition produces $67.2 \ L$ of oxygen gas at $0 \ ^\circ C$ and $1 \ atm$. The other product of decomposition is $KCl$. The initial mass of $KClO_3$ (in $g$) taken is:

Reaction of $x \ g$ of $Sn$ with $HCl$ quantitatively produced a salt. The entire amount of the salt reacted with $y \ g$ of nitrobenzene in the presence of the required amount of $HCl$ to produce $1.29 \ g$ of an organic salt (anilinium chloride) quantitatively.
$(1)$ The value of $x$ is. . . . .
$(2)$ The value of $y$ is. . . . .

The volume in $mL$ of $0.1 \ M$ solution of $NaOH$ required to completely neutralize $100 \ mL$ of $0.3 \ M$ solution of $H_3PO_3$ is

The heat of combustion of ethene $(C_2H_4)$ is $1411 \, kJ$. If a certain amount of ethene is burned to produce $6226 \, kJ$ of heat,what is the volume of $O_2$ (at $S.T.P.$) consumed in the process?

......... $cm^3$ is the volume of $0.1 \ N \ HCl$ required to react completely with $1.0 \ g$ of pure calcium carbonate $(Ca = 40, C = 12, O = 16)$.

How many moles of potassium chlorate need to be heated to produce $5.6 \, L$ of oxygen at $STP$?