$250 \, mL$ of a sodium carbonate solution contains $2.65 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is diluted to $1 \, L$,what is the concentration of the resultant solution? (Molecular weight of $Na_2CO_3 = 106$)

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:

What is the mole fraction of the solute in a $1 \, m$ (molal) aqueous solution?

What is the mole fraction of the solute in a $2.5 \, m$ aqueous solution?

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

What is the mole fraction of water in a spirit sample containing $92 \%$ ethyl alcohol by weight?