The volume of water which must be added to $40 \ cc$ of $0.25 \ M$ oxalic acid solution to make it exactly decimolar $(0.1 \ M)$ is $....... \ cc$.

The molarity of a solution containing $15 \text{ g}$ of $\text{NaOH}$ in $900 \text{ ml}$ of solution will be . . . . . . . (in $\text{ M}$)

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

If $23 \ g$ of ethanol ($C_2H_5OH$,molar mass $= 46 \ g \ mol^{-1}$) is dissolved in $500 \ mL$ of solution,find the molarity of the solution in $M$.

Two solutions of a substance (non-electrolyte) are mixed in the following manner: $480 \ mL$ of $1.5 \ M$ first solution $+ 520 \ mL$ of $1.2 \ M$ second solution. What is the molarity of the final mixture $.......... \ M$.

$A$ sample of drinking water was found to be severely contaminated with chloroform $(CHCl_{3})$,supposed to be a carcinogen. 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.