The formula of a gaseous hydrocarbon which requires $6$ times of its own volume of $O_{2}$ for complete oxidation and produces $4$ times its own volume of $CO_{2}$ is $C_{x}H_{y}$. The value of $y$ is $......$ .

The molarity of $HNO_{3}$ in a sample which has density $1.4 \; g/mL$ and mass percentage of $63\%$ is . . . . . . $M$.
(Molecular Weight of $HNO_{3} = 63$)

The volume of $0.1 \, M$ aqueous $KOH$ solution required for the complete neutralization of $20 \, mL$ of $0.1 \, M$ aqueous $H_3PO_3$ solution is .......... $mL$.

$A$ mixture of $CaCl_{2}$ and $NaCl$ weighing $4.44 \ g$ is treated with sodium carbonate solution to precipitate all the $Ca^{2+}$ ions as calcium carbonate. The calcium carbonate so obtained is heated strongly to get $0.56 \ g$ of $CaO$. The percentage of $NaCl$ in the mixture (atomic mass of $Ca=40$) is

What will be the volume of $CO_2$ at $S.T.P.$ obtained by heating $9.85 \ g$ of $BaCO_3$? (Atomic mass of $Ba = 137$)

$X \ g$ of $Ca$ [atomic mass $= 40$] dissolves completely in concentrated $HCl$ solution to produce $5.04 \ L$ of $H_2$ gas at $STP$. The value of $X$ is closest to