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 ........... $M$.

Molality of an aqueous solution of urea is $4.44 \ m$. Mole fraction of urea in solution is $x \times 10^{-5}$. Value of $x$ is. . . . . . (integer answer)

The unit of mole fraction is:

Equal volumes of liquid $A$ $(d = 0.8 \ g/mL)$ and liquid $B$ $(d = 1.2 \ g/mL)$ are mixed to form a solution. Calculate the mole fraction of $A$ in the solution $(M_A = 16, M_B = 32)$.

Which unit of concentration value does not change with change in temperature?

The mole fraction of a solute in a binary solution is $0.1$. At $298 \ K$,molarity of this solution is same as its molality. Density of this solution at $298 \ K$ is $2.0 \ g \ cm^{-3}$. The ratio of molecular weights of the solute and the solvent $(M_{solute} / M_{solvent})$ is: