1
JEE Advanced 2018 Paper 1 Offline
Numerical
+3
-0
Liquids A and B form ideal solution over the entire range of composition. At temperature $$T,$$ equimolar binary solution of liquids $$A$$ and $$B$$ has vapor pressure $$45$$ $$Torr.$$ At the same temperature, a new solution of $$A$$ and $$B$$ having mole fractions $${X_A}$$ and $${X_B}$$, respectively, has vapour pressure of $$22.5$$ $$Torr.$$ The value of $${x_A}/{x_B}$$ in the new solution is ___________.

(given that the vapor pressure of pure liquid $$A$$ is $$20$$ $$Torr$$ at temperature $$T$$)
2
JEE Advanced 2018 Paper 1 Offline
Numerical
+3
-0
The plot given below shows $$P-T$$ curves (where $$P$$ is the pressure and $$T$$ is the temperature) for two solvents $$X$$ and $$Y$$ and isomolal solutions of $$NaCl$$ in these solvents. $$NaCl$$ completely dissociates in both the solvents.

On addition of equal number of moles of a non-volatile solute $$S$$ in equal amount (in $$kg$$) of these solvents, the elevation of boiling point of solvent $$X$$ is three times that of solvent $$Y$$. Solute $$S$$ is known to undergo dimerization in these solvents. If the degree of dimerization is $$0.7$$ in solvent $$Y$$, the degree of dimerization in solvent $$X$$ is ___________.
3
JEE Advanced 2016 Paper 1 Offline
Numerical
+3
-0
The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 g cm–3 . The ratio of the molecular weights of the solute and solvent, $$\left( {{{M{W_{solute}}} \over {M{W_{solvent}}}}} \right)$$, is
4
JEE Advanced 2014 Paper 1 Offline
Numerical
+3
-0
MX2 dissociates in M2+ and X- ions in an aqueous solution, with a degree of dissociation ($$\alpha$$) of 0.5. The ratio of the observed depression of freezing point of the aqueous solution to the value of the depression of freezing point in the absence of ionic dissociation is