States of Matter

Phosphorus pentachloride dissociates as follows, in a closed reaction vessel,
PCl₅ (g) ⇌ PCl₃(g) + cl₂(g)
If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of PCl₅ is x, the partial pressure of PCl₃ will be

The formation of the oxide ion O^2-(g) requires first an exothermic and then an endothermic step as shown below

• Oxygen is more electronegative

• O^- ion has comparatively larger size than oxygen atom

• O^- ion will tend to resist the addition of another electron

• O^- ion will tend to resist the addition of another electron

As the temperature is raised from 20°C to 40°C, the average kinetic energy of neon atoms changes by a factor of which of the following?

• 1/2

• 2

• 313/293

• 313/293

In Vander Waals equation of state of the gas law, the constant ‘b’ is a measure of 

• intermolecular repulsions

• intermolecular collisions per unit volume

• Volume occupied by the molecules

• Volume occupied by the molecules

An ideal gas expands in volume from 1×10^-3 m³ to 1×10^-2 m³ at 300 K against a constant pressure of 1×10⁵ Nm^-2. The work done is

• -900 J

• 900 J

• 2780 J

• 2780 J

Which of the following has the dimension if [ML⁰T^-2]?

• Coefficient of viscosity

• Surface tension

• Vapour pressure

• Kinetic energy

The boiling points of HF, HCl, HBr and HI follow the order

• HF> HCl > HBr > HI

• HF> HI> HBr > HCl

• HI> HBr > HCl> H

• HCl > HF> HBr > HI

At a certain temperature, the value of the slope of the plot of osmotic pressure ($\mathrm{\pi }$) against concentration (C in molL^-1) of a certain polymer solution is 291R. The temperature at which osmotic pressure is measured, is (R is gas constant)

• 271°C

• 18°C

• 564 K

• 18 K

For one mole of an ideal gas, the slope of V vs. T curve at constant pressure of 2 atm is X L mol^-1 K^-1.The value of the ideal universal gas constant 'R' in terms of X is

• X L atm  mol^-1 K^-1

• x/2 L atm  mol^-1 K^-1

• 2X L atm  mol^-1 K^-1

• 2X atm L^-1 mol^-1 K^-1

At a certain temperature the time-required for the complete diffusion of 200 mL of H₂ gas is 30 min. The time required for the complete diffusion of 50 mL of O₂ gas at the same temperature will be

• 60min

• 30min

• 45min

• 15min