$10 \ g$ of a solute is dissolved in $90 \ g$ of a solvent. Its mass percent in solution is

What is molarity?

If the mole fraction of water in a solution of $H_2SO_4$ is $0.85$,then the molality of the solution is:

$2 \ g$ of substance $A$ is added to $18 \ g$ of water to form a solution. Calculate the mass percentage of the solute. (in $\%$)

The mole fraction of a solute in a $100$ molal aqueous solution is $.......... \times 10^{-2}$ (Round off to the nearest integer). [Given: Atomic masses: $H = 1.0 \ u$,$O = 16.0 \ u$]

How many grams of ethanol must be added to $1.0 \ kg$ of water to have a mole fraction of ethanol equal to $0.2$?