Air is an example of a solution of

Which of the following methods of expressing concentration does not change with temperature?

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

Which of the following modes of expressing concentration is independent of temperature?

$A$ sample of drinking water is severely contaminated with chloroform $(CHCl_3)$. $CHCl_3$ is considered 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.

For a very diluted solution,the preferred concentration unit is: