For a dilute solution having molality $m$ of a given solute in a solvent of molecular weight $\mathrm{M}$, boiling point ${\mathrm{T}}_b$ and heat of vaporisation per mole $∆\mathrm{H}; {\left[\frac{\partial {\mathrm{T}}_b}{\partial m}\right]}_{m\to 0}$ is equal to:

The phase diagrams for the pure solvent (solid lines) and the solution (non-volatile solute, dashed line) are recorded below: The quantity indicated by $\mathrm{L}$ in the figure is:

Three different ideal solutions (I, II, III) each containing total $10$ moles of $\mathrm{A} \& \mathrm{B}$ in different composition are taken as shown in figure and pressure over the solutions is gradually reduced.

Initially external pressure is same for all three solutions. At a particular external pressure $\left({\mathrm{P}}_1\right)$, ll solution is found to have

$\underset{(\mathrm{liq} \mathrm{composition})}{{\mathrm{X}}_{\mathrm{A}}=0.4 } \& \underset{(\mathrm{Vap}. \mathrm{composition})}{{\mathrm{Y}}_{\mathrm{A}}=0.8}$

Then select correct statement:

The vapour pressure of ideal solution of benzene and toluene is $550 \mathrm{torr}$ at $80°\mathrm{C}$ then what would be correct statement about same solution at $100°\mathrm{C}.$