The number of optical isomers possible for [Cr(C₂O₄)₃]^3$$-$$ is ____________.

Two flasks I and II shown below are connected by a valve of negligible volume.


When the valve is opened, the final pressure of the system in bar is x $$\times$$ 10^$$-$$2. The value of x is __________. (Integer answer)

[Assume - Ideal gas; 1 bar = 10⁵ Pa; Molar mass of N₂ = 28.0 g mol^$$-$$1; R = 8.31 J mol^$$-$$1 K^$$-$$1]

100 g of propane is completely reacted with 1000 g of oxygen. The mole fraction of carbon dioxide in the resulting mixture is x $$\times$$ 10^$$-$$2. The value of x is ____________. (Nearest integer)

[Atomic weight : H = 1.008; C = 12.00; O = 16.00]

40 g of glucose (Molar mass = 180) is mixed with 200 mL of water. The freezing point of solution is __________ K. (Nearest integer) [Given : K_f = 1.86 K kg mol^$$-$$1; Density of water = 1.00 g cm^$$-$$3; Freezing point of water = 273.15 K]