For the combustion reaction of $1 \ mol$ of benzene,if all reactants and products are in the gaseous state,then $\Delta n_{(g)}$ is equal to ......

$A$ sample of $NaNO_3$ weighing $0.38 \ g$ is placed in a $50.0 \ mL$ volumetric flask. The flask is filled to the mark with water. What is the molarity of the solution?

To a $25 \, mL$ of $H_2O_2$ solution,an excess of acidified solution of $KI$ was mixed. The liberated $I_2$ required $20 \, mL$ of $0.3 \, M$ hypo $(Na_2S_2O_3)$ solution for neutralization. The volume strength of $H_2O_2$ is......$mL$.

How many moles of ethene are required to prepare $6.0 \ g$ of ethane by the hydrogenation process (in $mole$)?

Volume of air needed for complete combustion of $10 \ L$ of $C_2H_4$ is :
$($Assume air contains $20\%$ of $O_2$ by volume$)$ (in $L$)

The molarity of $2 \, N \, HCl$ is .......