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

What is the molality of a solution which contains $18 \ g$ of glucose $(C_6H_{12}O_6)$ in $250 \ g$ of water?

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

$300 \ g$ of $25\%$ solution and $400 \ g$ of $40\%$ solution are mixed by weight. Calculate the percentage of the solute by weight in the final mixture. (in $\%$)

Match List-$I$ with List-$II$.

List-$I$ (Example)	List-$II$ (Type of Solution)
$A$. Humidity	$I$. Solid in solid
$B$. Alloys	$II$. Liquid in gas
$C$. Amalgams	$III$. Solid in gas
$D$. Smoke	$IV$. Liquid in solid

Choose the correct answer from the options given below:

Some amount of dichloromethane $(CH_2Cl_2)$ is added to $671.141 \ mL$ of chloroform $(CHCl_3)$ to prepare a $2.6 \times 10^{-3} \ M$ solution of $CH_2Cl_2$ $(DCM)$. The concentration of $DCM$ is $......... \ ppm$ (by mass). Given: Atomic mass: $C = 12, H = 1, Cl = 35.5$; density of $CHCl_3 = 1.49 \ g \ cm^{-3}$.