Two beakers of capacity 500 mL were taken. One of these beakers, labelled as “A”, was filled with 400 mL water whereas the beaker labelled “B“ was filled with 400 mL of 2M solution of NaCl. At the same temperature, both the beakers were placed in closed containers of the same material and the same capacity as shown in the figure.
            
At a given temperature, which of the following statements is correct about the vapour pressure of pure water and that of NaCl solution?

One mole of sugar is dissolved in three moles of water at 298 K. The relative lowering of vapour pressure is:

If 8 g of a non-electrolyte solute is dissolved in 114 g of n-octane to reduce its vapor pressure to 80 %, the molar mass (in g mol^–1) of the solute is:

[Molar mass of n-octane is 114 g mol^–1]

The vapour pressure of pure benzene at a certain temperature is 0.850 bar. A non-volatile, non-electrolyte solid weighing 0.5 g is added to 39.0 g of benzene (molar mass 78 g mol^–1). Vapour pressure of the solution, then, is 0.845 bar. The molar mass of the solid substance is:

The incorrect statement among the following is:

The mass of a non-volatile solute (molar mass 40 g mol^–1) that should be dissolved in 114 g octane to reduce its vapour pressure to 80 % would be:

1. 6 g

2. 7 g

3. 8 g

4. 10 g

The vapour pressure of 1 molal solution of a non-volatile solute in water at 300 K would be:

(The vapour pressure of water at 300 K = 12.3 kPa)

Benzene and toluene form an ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively.

The mole fraction of benzene in vapour phase, if 80 g of benzene is mixed with 100 g of toluene, would be:

1. 0.41

2. 0.68

3. 0.72

4. 0.59