$12 \ g$ of $Mg$ (atomic mass $24$) on reacting completely with acid gives hydrogen gas,the volume of which at $STP$ would be ............... $L$.

$23 \ g$ of sodium metal is reacted with water. Find the volume of $H_2$ gas evolved at $STP$ in $mL$.

The number of chlorine atoms in $1.98 \ g$ of $BaCl_2$ is ..... (Atomic weight of $Ba = 137$,$Cl = 35.5$)

$A$ $100 \ mL$ solution of $CH_3CH_2MgBr$ on treatment with methanol produces $2.24 \ mL$ of a gas at $STP$. The weight of gas produced is $......mg$. [nearest integer]

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 $HNO_{3} = 63$)

On electrical decomposition of $150 \ mL$ dry and pure $O_2$,$10\%$ of $O_2$ gets changed to $O_3$. The volume of the gaseous mixture after the reaction and the volume of the remaining gas left after passing through turpentine oil will be,respectively: