5

Q1. The zero point temperature is:

• 273 K
• 0^oC
• -273.15^oC
• 25^oC

Solution

The zero point temperature is -273.15^oC or 0 K.

Q2. The S.I unit of viscosity is:

• N m^-2s
• Nm^-1s^-1
• N m s
• Nm^-1 s²

Solution

The SI unit of viscosity is Nm^-2s.

Q3. A vessel contains 0.16g of methane and 0.28g of nitrogen. The ratio of partial pressures of methane to nitrogen in the mixture is about:

• 4 : 7
• 2 : 3
• 7 : 4
• 1 : 1

Solution

Partial pressure of a gas = mole fraction of that gas × Total pressure of mixture of the gases.

Q4. The property of a liquid that increases with a increase in temperature is:

• Viscosity
• Vapour pressure
• Surface tension
• Both Viscosity and Surface tension

Solution

On heating a liquid, its molecules get converted into vapour phase and thus increase the Vapour pressure of a liquid.

Q5. In dipole-induced dipole forces, the dipole moments (μ) of polar and non polar molecules are

• μ > 0 and μ = 0
• μ < 0 and μ > 0
• μ = 0 and μ < 0
• μ = 0 for both

Solution

The dipole-Induced dipole attractive forces operate between polar molecules having μ > 0 and the non-polar molecules having μ = 0.

Q6. The mass of 112 ml of N₂ at STP on liquefaction is:

• 0.28 g
• 0.14 g
• 0.56 g
• 0.84 g

Solution

112 ml of N₂ at S.T.P (1 atm, 0^oC) weighs

Q7. Sublimation involves the direct state change from:

• Liquid to solid
• Solid to liquid
• Gas to liquid
• Solid to gas

Solution

Sublimation involves the direct state conversion from solid to gas.

Q8. The vapour pressure of a liquid depends upon:

• Volume of liquid
• Surface area of liquid
• Nature of liquid
• Density of liquid

Solution

Vapour pressure depends upon nature of liquid and temperature.

Q9. General gas constant is represented by

• B
• K
• R
• S

Solution

General gas constant is represented by R.

Q10. Standard enthalpy of vaporization is taken at:

• 298 K
• 273 K
• 0^oC
• 25^oC

Solution

298 K is the standard temperature.

Q11. Vapour density of a diatomic elementary gas is 16. The atomic mass of gas is:

• 32
• 16
• 8
• 64

Solution

The atomic mass will be 16 g since the gas is diatomic.

Q12. The partial charges present on an atom are

• Greater than the unit charge
• Less than the unit charge
• Equal to the unit charge
• Does not depend on the unit charge

Solution

The partial charges present on an atom are always less than the unit charge (1.6 x 10^-19 C) because of electron sharing effect.

Q13. The strength of London forces do not increase with the increase in

• Molecular size
• Number of electrons
• Surface area of molecule
• The distance between two interacting particles

Solution

The strength of London forces increases with the increase in molecular size, number of electrons and surface area of molecule. But they are applicable only at short distances (500 pm).

Q14. Dalton's law of partial pressure states that

• The total pressure exerted by the mixture of non-reactive gases is equal to the sum of square of the partial pressures of individual gases.
• The total pressure exerted by the mixture of non-reactive gases is equal to the sum of the cube of the partial pressures of individual gases.
• The total pressure exerted by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases.
• The total pressure exerted by the mixture of non-reactive gases is equal to the product of the partial pressures of individual gases.

Solution

Dalton's law of partial pressure states that the total pressure exerted by the non reactive gas is equal to the sum of the partial pressures of individual gases.

Q15. Dipole-dipole forces are:

• Stronger than London forces
• Weaker than London forces
• Equal in strength to London forces
• Not comparable to London forces

Solution

Stronger than London forces.

Q16. A balloon seller filled a balloon with 2 L air when the temperature was 23.4^o C. He sold the balloon at the time when temperature was recorded to 26.1^oC.  Volume of the balloon at this temperature is

• 2.5 L
• 3.2L
• 2.018 L
• 1.24 L

Solution

 

Q17. The S.I unit of Surface tension is:

• Nm^-1
• Nm^-1s^-1
• Nms^-1
• Nm²s^-1

Solution

  Since the dimensions of surface energy are same as that of surface tension so the S.I unit of surface tension is also same as that of surface energy.  

Q18. A student was given Water, Benzene, Orange juice, and Glycerol to pipette out in four different beakers. The liquid that will be relatively difficult to be sucked into the pipette will be:

• Water
• Benzene
• Orange juice
• Glycerol

Solution

Among the given liquids Glycerol has the highest viscosity so it is relatively difficult to be sucked into the pipette.

Q19. Which of the following sublimes at ordinary temperature:

• Camphor
• Sodium chloride
• Sulphur
• Potassium

Solution

Camphor, iodine etc. sublime at ordinary temperature.

Q20. When the volume of a fixed mass of gas is doubled

• the pressure is halved
• the pressure is doubled
• the pressure goes up by four times
• the pressure goes down to a quarter

Solution

Pressure is inversely proportional to volume. Thus, when volume is doubled, the pressure is halved.

Q21. A gas will approach ideal behaviour at:

• Low temperature, low pressure
• Low temperature, high pressure
• High temperature, low pressure
• High temperature , high pressure

Solution

A gas will approach ideal behaviour at high temperature and low pressure.

Q22. Gases show positive deviations when:

• Effect of molecular attraction predominates
• a and b becomes zero
• Effect of molecular volume dominates
• Effect of molecular repulsions decreases

Solution

Gases show Z > 1 when effect of molecular volume dominates.

Q23. London forces are important only at:

• Short distances
• Long distances
• Infinite distance
• Distance between the two particles

Solution

London forces are important only at short distances (~500 pm).

Q24. London forces are also known as

• Keesom forces
• Dispersion forces
• vander Waals forces
• Dipole-dipole forces

Solution

London forces are also known as Dispersion forces.

Q25. Real gases behave much like an ideal gas at

• low pressure and high temperature
• low pressure and low temperature
• high pressure and high temperature
• high pressure and low temperature

Solution

Real gases behave much like an ideal gas at low pressure and high temperature.

Q26. A polar and a non-polar molecule interact by:

• Dipole-dipole forces
• London forces
• Hydrogen bond
• Dipole-induced dipole forces

Solution

Dipole-induced dipole forces operate between a polar molecule having a permanent dipole and a non-polar molecule lacking permanent dipole.

Q27. According to Boyle's law ______ .

• P x V = K
• P = V x K
• P/V = KT
• None of the above

Solution

According to Boyle's law, the temperature remaining constant, the volume of a given mass of dry gas is inversely proportional to its pressure. P x V = K = Constant

Q28. Vapour pressure of a liquid decreases with increase in:

• Temperature
• Pressure
• Viscosity
• Polarity of liquid molecules

Solution

Vapour pressure decreases with increase in polarity of liquid molecules.

Q29. According to the kinetic theory of gases, between two successive collisions of a gas molecule in an ideal gas travels

• In a circular path
• In a wavy path
• In a straight line path
• With accelerated velocity

Solution

The molecule of an ideal gas travels in a straight line path between two successive collisions.

Q30. A strong type of dipole-dipole interaction is:

• Covalent bond
• Hydrogen bond
• Ionic bond
• Electrostatic bond

Solution

A strong type of dipole-dipole interaction is hydrogen bond but only a few elements can participate in hydrogen bond formation.

Q31. A gas exerts a pressure of 0.892 atm in a 5.00 L container at 15º C. The density of the gas is 1.22 g/L. What is the molecular weight of the gas?

• 32 g/mol
• 32.3 g/mol
• 33.2 g/mol
• 33 g/mol

Solution

T = 273 + 15 = 288 K PV = nRT 0.892 x 5 = n x 0.0821 x 288 n = 0.189 mol (molecular weight) = 32.3g / mol.

Q32. A liquid enclosed in 1.0L flask at 298K. The vapour pressure exerted by the liquid is 20.0 mm. when the same liquid is enclosed in a flask of 5L capacity at the same temperature, the vapour pressure of the liquid will be:

• 1000mm
• 10mm
• 40mm
• 20.0mm

Solution

The vapour pressure of a liquid depends only on the nature of the liquid and the temperature. It does not depend on the volume of the container so it is 20.0mm.

Q33. The vapour pressure of water at 300 K in a closed container is 0.4 atm. If the volume of container is doubled, its vapour pressure at 300 K will be:

• 0.8 atm
• 0.2 atm
• 0.4 atm
• 0.6 atm

Solution

The vapour pressure of water will remain same as the temperature is unchanged.

Q34. The ideal gas equation is:

• pV = nR/T
• p = VnRT
• pV = n/RT
• pV = nRT

Solution

The ideal gas equation is pV = nRT.

Q35. At constant temperature, the pressure of a fixed amount of gas varies inversely with its volume, is

• Gay Lussac's law
• Avogadro law
• Boyle's law
• Charles' law

Solution

Boyle's law states that the volume of a fixed mass of a gas is inversely proportional to its pressure at constant temperature.

Q36. The influence of permanent electrical dipole in dipole-Induced Dipole forces

• Increases with the increase in size of the molecule
• Decreases with the decrease in size of the molecule
• Does not depend on the size of the molecule
• Depend on the ionic radii

Solution

Induced dipole moment depends upon the dipole moment of the permanent dipole and the polarizability of the electrically neutral molecule. As the size of molecule or atom increase, the influence of permanent electrical dipole on it also increases.

Q37. Choose the odd one out for ideal gas.

• They have point masses
• Ideal gas has molecules with no volume themselves
• Have inelastic collisions
• Have no attractive forces

Solution

Ideal gases have perfectly elastic collisions.

Q38. The phenomenon responsible for spherical shape of liquid drops is:

• Interference
• Diffraction
• Surface tension
• Viscosity

Solution

A sphere has a minimum surface area

Q39. The graph of variation in volume (V) plotted against pressure (P) at a constant temperature is _______ .

• hyperbolic
• straight line passing through origin
• straight line paralled to X-axis
• parabolic

Solution

Q40. Dipole-dipole forces act between molecules possessing:

• Electronic charges
• Permanent dipole
• Induced dipole
• No dipole moment