If the mole fraction of the solute in liquid naphthalene $(C_{10}H_{8})$ is $0.2$,then the molality of the solution will be ............ $m$.

$2 \ g$ of substance $A$ is added to $18 \ g$ of water to form a solution. Calculate the mass percentage of the solute. (in $\%$)

To prepare a solution of concentration $0.03 \ g/mL$ of $AgNO_3$,what amount of $AgNO_3$ should be added in $60 \ mL$ of solution?

The number of moles of $NaOH$ in $2 \ L$ of $0.5 \ M \ NaOH$ solution is ..........

$A$ sample of drinking water was found to be severely contaminated with chloroform,$CHCl_{3}$,supposed to be carcinogenic in nature. The level of contamination was $15 \ ppm$ (by mass).
$(i)$ Express this in percent by mass.
$(ii)$ Determine the molality of chloroform in the water sample.

Calculate the molarity if $30 \, mL$ of $0.5 \, M$ $H_2SO_4$ is diluted to $500 \, mL$. (in $, M$)