$4 \ g$ of $NaOH$ is dissolved in $250 \ mL$ of water to prepare a solution. Find the molarity of the solution. (in $M$)

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

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

Calculate the mole fraction of urea in an aqueous solution of $1 \ m$ urea $(NH_2CONH_2)$.

$A$ solution of sodium sulphate contains $92 \ g$ of $Na^{+}$ ions per kilogram of water. The molality of $Na^{+}$ ions in that solution in $mol \ kg^{-1}$ is:

Calculate the mass of urea $(NH_2CONH_2)$ required in making $2.5 \, kg$ of $0.25 \, \text{molal}$ aqueous solution.