One litre oxygen gas at $STP$ will weigh $.................. \ g$

$A$ $1.84 \, mg$ sample of polyhydric alcoholic compound '$X$' of molar mass $92.0 \, g/mol$ gave $1.344 \, mL$ of $H_2$ gas at $STP$. The number of alcoholic hydrogens present in compound '$X$' is $.....$

$X$ litres of carbon monoxide is present at $STP$. It is completely oxidized to $CO_2$. The volume of $CO_2$ formed is $11.207$ litres. What is the value of $X$ in litres?

Molarity of a given orthophosphoric acid solution is $3 \ M$. Its normality is (in $N$)

$X$ litre of carbon monoxide is present at $STP$. It is completely oxidized to $CO_2$. The volume of $CO_2$ formed is $11.207 \ L$. What is the value of $X$ in litres?

$CaCO_3$ reacts with $HCl$ to produce $CaCl_2, CO_2$ and $H_2O$. The approximate mass (in $g$) of $CaCO_3$ required to react completely with $25 \ mL$ of $0.75 \ M \ HCl$ is (atomic mass of $Ca=40, C=12, O=16, Cl=35.5$ and $H=1$).