Mixing of two different ideal gases under isothermal reversible condition will lead to

• increase of Gibbs free energy of the system

• no change of entropy of the system

• increase of entropy of the system

• increase of enthalpy of the system

32.

Two gases X (molecular weight M_X) and Y (molecular weight My; M_y > M_x) are at the same temperature T in two different containers. Their root mean square velocities are C_x and C_y respectively. If the average kinetic energies per molecule of two gases X and Y are E_x and E_y respectively then which of the following relation(s) is(are) true?

• E_x >E_y

• C_x > C_y

• E_x = E_y =(3/2)RT

• E_x = E_y =(3/2)k_BT

Equal weights of CH₄ and H₂ are mixed in an empty container at 25°C. the fraction of the total pressure exerted by H₂ is

• 1/9

• 1/2

• 8/9

• 16/17

Which of the following has least covalent P-H bond?

• PH₃

• P₂H₆

• P₂H₅

• PH${}_6^{+}$

A gaseous mixture containing He, CH₄ and SO₂ was allowed to effuse through a fine hole then find what molar ratio of gases coming out initially? (Given mixture contains He, CH₄ and SO₂ in 1 : 2: 3 mole ratio).

• $\sqrt{2}:\sqrt{2}: 3$

• 2: 2: 3

• 4: 4: 3

• 1: 1: 3

NH₄Cl (s) is heated in a test tube. Vapours are brought in contact with red litmus paper, which changes it to blue and then to red. It is because of

• formation of NH₄OH and HCl

• formation of NH₃ and HCl

• greater diffusion of NH₃ than HCl

• greater diffusion of HCl than NH₃

The pressure exerted by 6.0g of methane gas in a 0.03 m³ vessel at 129°C is (Atomic masses: C = 12.01, H = 1.01 and R= 8.314JK^-1 mol^-1)

• 215216 Pa

• 13409 Pa

• 41648 Pa

• 31684 Pa

A bubble of air is underwater at temperature 15°C and the pressure 1.5 bar. If the bubble rises to the surface where the temperature is 25°C and the pressure is 1.0 bar, what will happen to the volume of the bubble?

• Volume will become greater by a factor of 1.6

• Volume will become greater by a factor of 1.1

• Volume will become smaller by a factor of 0.70

• Volume will become greater by a factor of 2.9

Two glass bulbs A and B are connected by a very small tube having a stop-cock. Bulb A has a volume of 100 cm³ and contained the gas while bulb B was empty. On opening stop-clock, the pressure fell down to 40%. The volume of the bulb B must be

• 75 cm³

• 125 cm³

• 150 cm³

• 250 cm³

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

• 900 cal K^-1mol^-1

• 6.21 X 10^-21 JK^-1 molecule^-1

• 336.7 JK^-1 molecule^-1

• 3741.3 JK^-1 mol^-1