What is the mole fraction of the solute in a $1 \, m$ (molal) aqueous solution?

$A$ $2.0 \, M$ solution is obtained when $0.5 \, mole$ of solute is dissolved in:

$A$ sample of drinking water is found to be severely contaminated with chloroform $(CHCl_3)$,which is a suspected carcinogen. If the level of contamination is $15 \ ppm$ (by mass),express this in percentage by mass.

$10.30 \; mg$ of $O_2$ is dissolved in $1 \; L$ of seawater with a density of $1.03 \; g/mL$. The concentration of $O_2$ in $ppm$ is:

If the molality of an aqueous solution is $m$ and the mole fraction of the solute is $y$,which of the following relations is correct?

What is the molarity of a solution containing $3.2 \ g$ of $NaOH$ (molar mass $40 \ g \ mol^{-1}$) in $250 \ cm^{3}$ of water?