A solution at ${\text{20}}^{\text{o}}\text{C}$ is composed of 1.5 mol of benzene and 3.5 mol of toluene. If the vapour pressure of pure benzene and pure toluene at this temperature are 74.7 torr and 22.3 torr respectively, then the total vapour pressure of the solution and the benzene mole fraction in equilibrium with it will be, respectively:

If $80 \mathrm{g}$ of copper sulphate ${\mathrm{CuSO}}_4·5{\mathrm{H}}_2\mathrm{O}$ is dissolved in deionised water to make $5 \mathrm{L}$ of solution. The concentration of the copper sulphate solution is $x\times {10}^{-3}\text{ mol }{L}^{-1}.$ The value of $x$ is _____.

$[\text{Atomic masses }\mathrm{Cu} : 63.54\mathrm{u}, \mathrm{S} : 32\mathrm{u}, \mathrm{O} : 16\mathrm{u}, \mathrm{H} : 1\mathrm{u}]$

A company dissolves '$\mathrm{x}$' amount of ${\mathrm{CO}}_2$ at $298 \mathrm{K}$ in $1$ litre of water to prepare soda water. $\mathrm{x}=.......\times {10}^{-3} \mathrm{g}$. (nearest integer)

(Given: partial pressure of ${\mathrm{CO}}_2$ at $298 \mathrm{K}=0.835$ bar. Henry's law constant for ${\mathrm{CO}}_2$ at $298 \mathrm{K}=1.67 \mathrm{kbar}$. Atomic mass of $\mathrm{H},\mathrm{C}$ and $\mathrm{O}$ is $1,12$, and $6 \mathrm{g}{ \mathrm{mol}}^{-1}$, respectively)

Solute A associates in water. When $0.7 \mathrm{g}$ of solute $\mathrm{A}$ is dissolved in $42.0 \mathrm{g}$ of water, it depresses the freezing point by $0.2 °\mathrm{C}$. The percentage association of solute $\mathrm{A}$ in water, is

[Given: Molar mass of $\mathrm{A}=93 \mathrm{g}{ \mathrm{mol}}^{-1}$. Molal depression constant of water is $1.86 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$]

Given below are two statements : one is labelled as Assertion and the other is labelled as Reason.

Assertion: At $10 °\mathrm{C}$, the density of a $5 \mathrm{M}$ solution of $\mathrm{KCl}$ [atomic masses of $\mathrm{K} \& \mathrm{Cl}$ are $39 \& 35.5 \mathrm{g}{ \mathrm{mol}}^{-1}$ respectively], is '$\mathrm{x}$' ${\mathrm{gml}}^{-1}$. The solution is cooled to $-21 °\mathrm{C}$. The molality of the solution will remain unchanged.

Reason: The molality of a solution does not change with temperature as mass remains unaffected with temperature.

In the light of the above statements, choose the correct answer from the options given below.