$A$ solution of sulfuric acid contains $80\%$ $H_2SO_4$ by weight and has a specific gravity of $1.71$. What is its normality?

What quantity of oxygen is required for complete burning of $15.6 \ g$ benzene (in $g$)?

$1.84 \ g$ of a mixture of $CaCO_3$ and $MgCO_3$ is strongly heated to get a residue of $0.96 \ g$. The percentage of $CaCO_3$ in the mixture is

How many litres of oxygen (at $STP$) are required for complete combustion of $39 \ g$ of liquid benzene?
(Atomic weights: $C=12, O=16, H=1$)

What volume (in $mL$) of $HCl$ solution containing $73 \ g$ per litre is required to completely neutralise sodium hydroxide solution,obtained by allowing $0.46 \ g$ of metallic sodium to act upon water?

When a hydrated salt,$Na_2SO_4 \cdot nH_2O$,is heated,it loses $56\%$ of its weight and becomes anhydrous. What is the approximate value of $n$?