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)

$A$ sample of drinking water is found to be severely contaminated with chloroform $(CHCl_3)$,which is a suspected carcinogen. The level of contamination is $15 \ ppm$ (by mass). Calculate the molarity of chloroform in the water sample.

$A$ compound $H_2X$ with molar weight of $80 \ g \ mol^{-1}$ is dissolved in a solvent having density of $0.4 \ g \ mL^{-1}$. Assuming no change in volume upon dissolution,the molality of a $3.2 \ M$ solution is:

Calculate the molarity of a solution prepared by dissolving $7.1 \ g$ of sodium sulfate $(Na_2SO_4)$ in water to make $100 \ mL$ of solution. (in $M$)

Explain the concept of reactions in solutions and mass percentage.

The molecular weight of glucose is $180$. $A$ solution of glucose which contains $18 \ g$ per litre is ........... $molal$.