A gas can be liquefied at temperature T and pressure p provided

• T = T_c and p < p_c

• T < T_c and p > p_c

• T > T_c and p > p_c

• T > T_c and p < p_c

The dispersed phase and dispersion medium of fog respectively are

• solid, liquid

• liquid, liquid

• liquid, gas

• gas, liquid

The units of surface tension and viscosity of liquids respectively are

• kg m^-1s^-1, Nm^-1

• kg s^-2, kg m^-1 s^-1

• Nm^-1, kg m^-1s^-2

• kg s^-1, kg m^-2s^-1

Assertion : CHCl₃ and CH₃OH are miscible.

Reason : One of them is polar.

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

• If Assertion is true but Reason is false.

• If Assertion is false but Reason is true.

415.

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

• $\frac{\mathrm{X}}{2}$L atm mol^-1 K^-1

• 2X L atm mol^-1 K^-1

• 2 X 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

• 60 min

• 30 min

• 45 min

• 15 min

Assertion: An increase in surface area increases the rate of evaporation.
Reason: Stronger the intermolecular attractive forces, fast is the rate of evaporation at a given temperature.

• If both assertion and reason are true and reason is a correct explanation of the assertion.

• If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both the assertion and reason are false.

Assertion: Atoms can neither be created nor destroyed.
Reason: Under the similar condition of temperature and pressure, an equal volume of gases does not contain an equal number of atoms.

• If both assertion and reason are true and reason is a correct explanation of the assertion.

• If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both the assertion and reason are false.

Equal weights of CH₃ 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

Four gases P, Q, R and S have almost same values of 'b' but their 'a' values (a, b are van der Waals' constants) are in the order Q < R < S < P. At a particular temperature, among the four gases, the most easily liquefiable one is

• P

• Q

• R

• S