A certain mass of a gas occupies a volume of 2L at STP. To what temperature the gas must be heated to double its volume, keeping the pressure constant ?

• 100 K

• 273 K

• 273°C

• 546°C

The average kinetic energy of one molecule of an ideal gas at 27°C and 1 atm pressure is

• 900 cal K^-1 mol^-1

• 6.21 × 10^-21 JK^-1 molecule^-1

• 336.7 JK^-1 molecule^-1

• 3741.3 JK^-1 mol^-1

CH₄ diffuses two times faster than a gas X. The number of molecules present in 32 g ofgas X is (N is Avogadro number)

• N

• N/2

• N/4

• N/16

Under which one of the following conditions do real gases approach the ideal gas behaviour?

• Low temperature and high pressure

• High temperature and high pressure

• High temperature and low pressure

• Low temperature and low pressure

Which one of the following is the ratio of the lowering of vapour pressure of 0.1 M , aqueous solutions of BaCl₂, NaCl and Al₂SO₃ respectively?

• 3 : 2 : 5

• 5 : 2 : 3

• 5 : 3 : 2

• 2 : 3 : 5

Which one of the following equations represents the variation of viscosity coefficient (η) with temperature (T)?

• η= Ae^-E/RT

• η= Ae^E/RT

• η= Ae^-E/kT

• η= Ae^-E/T

Assertion (A): van der Waals' forces are reponsible for chemisorptions.

Reason (R): High temperature is favourable for chemisorptions.

The correct answer is:

• (A) is false, but (R) is true

• Both (A) and (R) are correct and (R) is the correct explanation of A

• Both (A) and (R) are correct and (R) is not the correct explanation of (A)

• (A) is true, but (R) is false

278.

Which one of the following is the wrong statement about the liquid?

• It has intermolecular force of attraction.

• Evaporation of liquids increase with the decrease of surface area.

• It resembles a gas near the cnt1cal temperature.

• lt is an intermediate state between gaseous and solid state.

Which one of the following is applicable for an adiabatic expansion of an ideal gas?

• $∆$E = 0

• $∆\mathrm{W} = ∆\mathrm{E}$

• $∆\mathrm{W} = -∆\mathrm{E}$

• $∆\mathrm{W} = 0$

The ratio of rates of diffusion of gases X and Y is 1 : 5 and that of Y and Z is 1 : 6. The ratio of rates of diffusion of Z and X is

• 1:30

• 1:6

• 30:1

• 6:1