$A$ solution is $0.25 \%$ by mass. What is the weight of solvent containing $1.25 \ g$ solute (in $g$)?

When $6 \ g$ of urea is dissolved in $180 \ g$ of $H_2O$,the mole fraction of urea is:

Density of a $2.05 \ M$ solution of acetic acid in water is $1.02 \ g/mL$. The molality of the solution is ............. $mol \ kg^{-1}$.

The density of $NaOH$ solution is $1.2 \, g \, cm^{-3}$. The molality of this solution is $.... \, m$ (Round off to the nearest integer). [Use: Atomic masses: $Na: 23.0 \, u, O: 16.0 \, u, H: 1.0 \, u$]

If the molality of an aqueous solution is $m$ and the mole fraction of the solute is $y$,which of the following relations is correct?

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