If the concentration of $Al^{3+}$ in an aqueous solution of $Al_2(SO_4)_3$ is $0.28 \ M$,then the concentration of $(SO_4)^{2-}$ ion is ........... $M$.

$A$ 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.

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

Which of the following methods of expressing concentration are unitless?

$x \ g$ of $NaCl$ is added to water in a beaker with a lid. The temperature of the system is raised from $1^{\circ}C$ to $25^{\circ}C$. Which out of the following plots is best suited for the change in the molarity $(M)$ of the solution with respect to temperature? [Consider the solubility of $NaCl$ remains unchanged over the temperature range]

If a solution of methyl alcohol $(CH_3OH)$ is $5.2 \ m$ (molal) in water,what is the mole fraction of methyl alcohol in the solution?