The hardness of a water sample is due to $50 \, ppm$ of $MgSO_4$. Calculate the amount of $MgSO_4$ in $mg$ present per $kg$ of water.

Calculate the amount of benzoic acid $(C_{6}H_{5}COOH)$ required for preparing $250 \ mL$ of $0.15 \ M$ solution in methanol.

What is the sum of the mole fractions of all the components in a solution?

What volume (in $mL$) of $3.0 \ M \ H_2SO_4$ is required to prepare $1.0 \ L$ of a $1.0 \ M$ solution?

State whether the following sentences are true $(T)$ or false $(F)$.
$(a)$ Concentration of pure water is $1.0 \ mol \ L^{-1}$.
$(b)$ Concentration of pure water is $55.5 \ mol \ L^{-1}$.

$3.0 \ g$ ethanoic acid in $50 \ g$ benzene has . . . . . . molality. (Atomic weights: $H=1, C=12, O=16$).