The molality of $90\%$ ${H_2SO_4}$ solution is [density $= 1.8 \ g/mL$].

$A$ 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 mole fraction of urea in an aqueous solution of $1 \ m$ urea $(NH_2CONH_2)$.

If the density of a solution is $1.17 \, g/cc$,what is the molarity of liquid $HCl$?

If the mole fraction of ethanol in a solution made by mixing $x \text{ g}$ of water and $69 \text{ g}$ of ethanol is $0.6$, then $x = \dots \dots \dots \dots$

The molality of $648 \ g$ of pure water is ........... $m$.