How many grams of ethanol are required to obtain $280 \ mL$ of dihydrogen gas at $S.T.P.$ by the reaction of $C_2H_5OH$ with $Na$ metal? (Molar mass of ethanol = $46 \ g/mol$)

Calculate the molarity $(M)$ of a $H_2SO_4$ solution that has a density of $1.84 \ g/mL$ and is $98 \% \, w/w$.

$X \ g$ 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

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

Concentrated nitric acid is labelled as $75 \%$ by mass. The volume in $mL$ of the solution which contains $30 \ g$ of nitric acid is $.............$ Given : Density of nitric acid solution is $1.25 \ g / mL$

$4.4 \ g$ of an unknown gas occupies $2.24 \ L$ of volume at standard temperature and pressure. The gas may be