{TOPIC 1: Intermolecular Forces, Gas Laws and Ideal Gas Equation}

1. Which of the following is not a type of van der Waal's forces?

(a) Dipole - dipole forces

(b) Dipole - induced dipole forces

(c) Ion - dipole forces

(d) London forces

2. Gas equation \(P V=n R T\) is obeyed by

(a) only isothermal process

(b) only adiabatic process

(c) both (a) and (b)

(d) none of these

3. Air at sea level is dense. This is a practical application of

(a) Boyle's law

(b) Charle's law

(c) Kelvin's law

(d) Brown's law

4. "Equal volumes of all gases at the same temperature and pressure contain equal number of particles." This statement is a direct consequence of :

(a) Perfect gas law

(b) Avogadro's law

(c) Charle's law

(d) Boyle's law

5. A gas in an open container is heated from \(27^{\circ} \mathrm{C}\) to \(127^{\circ} \mathrm{C}\). The fraction of the original amount of the gas remaining in the container will be

(a) \(3 / 4\)

(b) \(1 / 2\)

(c) \(1 / 4\)

(d) \(1 / 8\)

6. The pressure exerted by \(6.0 \mathrm{~g}\) of methane gas in a \(0.03 \mathrm{~m} 3\) vessel at \(129^{\circ} \mathrm{C}\) is (Atomic masses : \(\mathrm{C}=\) \(12.01, \mathrm{H}=1.01\) and \(\mathrm{R}=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) )

(a) \(31684 \mathrm{~Pa}\)

(b) \(215216 \mathrm{~Pa}\)

(c) \(13409 \mathrm{~Pa}\)

(d) \(41648 \mathrm{~Pa}\)

7. Two flasks \(A\) and \(\mathrm{B}\) of \(500 \mathrm{~mL}\) each are respectively filled with \(\mathrm{O}_{2}\) and \(\mathrm{SO}_{2}\) at \(300 \mathrm{~K}\) and \(1 \mathrm{~atm}\) pressure. The flasks will contain

(a) the same number of atoms

(b) the same number of molecules

(c) more number of moles of molecules in flask A as compared to flask B

(d) the same amount of gases

8. Dalton's law of partial pressure will not apply to which of the following mixture of gases

(a) \(\mathrm{H}_{2}\) and \(\mathrm{SO}_{2}\)

(b) \(\mathrm{H}_{2}\) and \(\mathrm{Cl}_{2}\)

(c) \(\mathrm{H}_{2}\) and \(\mathrm{CO}_{2}\)

(d) \(\mathrm{CO}_{2}\) and \(\mathrm{Cl}_{2}\)

9. Dipole-induced dipole interactions are present in which of the following pairs : 

(a) \(\mathrm{Cl}_{2}\) and \(\mathrm{CCl}_{4}\)

(b) \(\mathrm{HCl}\) and \(\mathrm{He}\) atoms

(c) \(\mathrm{SiF}_{4}\) and \(\mathrm{He}\) atoms

(d) \(\mathrm{H}_{2} \mathrm{O}\) and alcohol

10. The pressure of sodium vapour in a \(1.0 \mathrm{~L}\) container is 10 torr at \(1000{ }^{\circ} \mathrm{C}\). How many atoms are in the container?

(a) \(9.7 \times 10^{17}\)

(b) \(7.6 \times 10^{19}\)

(c) \(4.2 \times 10^{17}\)

(d) \(9.7 \times 10^{19}\)

11. The atmospheric pressure on Mars is \(0.61 \mathrm{kPa}\). What is the pressure in mm Hg?

(a) 0.63

(b) 4.6

(c) 6.3

(d) 3.2

12. \(56 \mathrm{~g}\) of nitrogen and \(96 \mathrm{~g}\) of oxygen are mixed isothermaly and at a total pressure of \(10 \mathrm{~atm}\). The partial pressures of oxygen and nitrogen (in atm) are respectively:

(a) 4, 6

(b) 5,5

(c) 2,8

(d) 6, 4

13. What is the ratio of diffusion rate of oxygen to hydrogen?

(a) \(1: 4\)

(b) \(4: 1\)

(c) \(1: 8\)

(d) \(8: 1\)

14. Which of following graph(s) represents Boyle's law

(a) Only I

(b) II and IV

(c) I and III

(d) Only III

15. Pressure remaining the same, the volume of a given mass of an ideal gas increases for every degree centigrade rise in temperature by definite fraction of its volume at

(a) \(0^{\circ} \mathrm{C}\)

(b) its critical temperature

(c) absolute zero

(d) its Boyle's temperature

16. The ratio of the rate of diffusion of helium and methane under identical condition of pressure and temperature will be

(a) 4

(b) 2

(c) 1

(d) 0.5

17. A gas diffuses \(1 / 5\) times as fast as hydrogen. Its molecular weight is

(a) 50

(b) 25

(c) \(25 \sqrt{2}\)

(d) \(50 \sqrt{2}\)

18. Which of the following are arranged in the correct order?

I. Gas \(>\) Liquid \(>\) Solid (Thermal energy)

II. Solid \(>\) Liquid \(>\) Gas (Intermolecular force)

Select the correct option.

(a) I only

(b) II only

(c) Both I and II

(d) None of these

19. At N.T.P the volume of a gas is found to be \(273 \mathrm{~mL}\). What will be the volume of this gas at \(600 \mathrm{~mm}\) of \(\mathrm{Hg}\) and \(273^{\circ} \mathrm{C}\) ?

(a) \(391.8 \mathrm{~mL}\) (b) \(380 \mathrm{~mL}\)

(c) \(691.6 \mathrm{~mL}\)

(d) \(750 \mathrm{Ml}\)

20. If three unreactive gases having partial pressures \(P_{A}, P_{B}\) and \(P_{C}\) and their moles are 1,2 and 3 respectively then their total pressure will be

(a) \(\mathrm{P}=\mathrm{P}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}+\mathrm{P}_{\mathrm{C}}\)

(b) \(\mathrm{P}=\frac{\mathrm{P}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}+\mathrm{P}_{\mathrm{C}}}{6}\)

(c) \(\mathrm{P}=\frac{\sqrt{\mathrm{P}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}+\mathrm{P}_{\mathrm{C}}}}{3}\)

(d) None of these

21. For 1 mol of an ideal gas at a constant temperature \(T\), the plot of \((\log P)\) against \((\log V)\) is a \((P\) : Pressure, \(V\) : Volume)

(a) Straight line parallel to \(x\)-axis.

(b) Straight line with a negative slope.

(c) Curve starting at origin.

(d) Straight line passing through origin.

22. What is the value of \(\mathrm{X}\) in \({ }^{\circ} \mathrm{C}\) for given volume vs temperature curve ? 

(a) \(0^{\circ} \mathrm{C}\)

(b) \(273.15^{\circ} \mathrm{C}\)

(c) \(-273.15^{\circ} \mathrm{C}\)

(d) \(300^{\circ} \mathrm{C}\)

23. \(4.4 \mathrm{~g}\) of a gas at STP occupies a volume of \(2.24 \mathrm{~L}\), the gas can be

(a) \(\mathrm{O}_{2}\)

(b) \(\mathrm{CO}\)

(c) \(\mathrm{NO}_{2}\)

(d) \(\mathrm{CO}_{2}\)

24. A certain gas takes three times as long to effuse out as helium. Its molecular mass will be :

(a) \(27 \mathrm{u}\)

(b) \(36 \mathrm{u}\)

(c) \(64 \mathrm{u}\)

(d) \(9 \mathrm{u}\)

25. The correct value of the gas constant ' \(R\) ' is close to :

(a) 0.082 litre-atmosphere \(\mathrm{K}\)

(b) 0.082 litre-atmosphere \(\mathrm{K}^{-1} \mathrm{~mol}^{-1}\)

(c) 0.082 litre - atmosphere \(^{-1} \mathrm{~K} \mathrm{~mol}^{-1}\)

(d) 0.082 litre -1 atmosphere \(^{-1} \mathrm{~K}\) mol

26. \(500 \mathrm{~mL}\) of air at \(760 \mathrm{~mm}\) pressure were compressed to \(200 \mathrm{~mL}\). If the temperature remains constant, what will be the pressure after compression?

(a) \(1800 \mathrm{~mm}\) (b) \(1900 \mathrm{~mm}\)

(c) \(2000 \mathrm{~mm}\)

(d) \(1500 \mathrm{~mm}\)

27. At a pressure of 760 torr and temperature of \(273.15 \mathrm{~K}\), the indicated volume of which system is not consistent with the observation

(a) \(14 \mathrm{~g}\) of \(\mathrm{N}_{2}+16 \mathrm{~g}\) of \(\mathrm{O}_{2} ;\) Volume \(=22.4 \mathrm{~L}\)

(b) \(4 \mathrm{~g}\) of \(\mathrm{He}+44 \mathrm{~g}\) of \(\mathrm{CO}_{2} ;\) Volume \(=44.8 \mathrm{~L}\)

(c) \(7 \mathrm{~g}\) of \(\mathrm{N}_{2}+36 \mathrm{~g}\) of \(\mathrm{O}_{3}\); Volume \(=22.4 \mathrm{~L}\)

(d) \(17 \mathrm{~g}\) of \(\mathrm{NH}_{3}+36.5 \mathrm{~g}\) of \(\mathrm{HCl}\), Volume \(=44.8 \mathrm{~L}\)

28. One mole of gas A and three moles of a gas B are placed in flask of volume 100 litres at \(27^{\circ} \mathrm{C}\). Calculate the total partial pressure of the gases in the mixture.

(a) \(1.0 \mathrm{~atm}\). (b) \(0.9 \mathrm{~atm}\)

(c) \(0.985 \mathrm{~atm}\)

(d) \(10.850 \mathrm{~atm}\).

29. Which of the following volume (V) - temperature (T) plots represents the behaviour of one mole of an ideal gas at one atmospheric pressure ?

30. A mixture of \(16 \mathrm{~g} \mathrm{CH}_{4}\) and \(64 \mathrm{~g}\) of \(\mathrm{O}_{2}\) is ignited in a sealed bulb of \(3 \mathrm{~L}\) and then cooled to \(27{ }^{\circ} \mathrm{C}\). The pressure in the bulb will be

(a) \(0.82 \mathrm{~atm}\)

(b) \(8.2 \mathrm{~atm}\)

(c) \(24.6 \mathrm{~atm}\)

(d) \(2.46 \mathrm{~atm}\)

\section{TOPIC 2: Kinetic Theory of Gases and Molecular Speeds}

31. The ratio between most probable velocity, mean velocity and r.m.s velocity is :

(a) \(\sqrt{2}: \sqrt{8 / \pi}: \sqrt{3}\)

(b) \(\sqrt{2}: \sqrt{3}: \sqrt{8 / \pi}\)

(c) \(1: 2: 3\)

(d) \(1: \sqrt{2}: \sqrt{3}\)

32. As the temperature is raised from \(20^{\circ} \mathrm{C}\) to \(40^{\circ} \mathrm{C}\), the average kinetic energy of neon atoms changes by a factor of which of the following ?

(a) \(\frac{313}{293}\)

(b) \(\sqrt{(313 / 293)}\)

(c) \(1 / 2\)

(d) 2

33. Boyle's law, according to kinetic equation can be expressed as 

(a) \(\mathrm{PV}=\mathrm{KT}\)

(b) \(\mathrm{PV}=\mathrm{RT}\)

(c) \(\mathrm{PV}=\frac{3}{2} \mathrm{kT}\)

(d) \(P V=\frac{2}{3} \mathrm{kT}\)

34. The r.m.s velocity of \(\mathrm{CO}_{2}\) at temperature \(\mathrm{T}\) (in kelvin) is \(x \mathrm{cms}^{-1}\). At what temperature (in kelvin) the r.m.s. velocity of nitrous oxide would be \(4 \mathrm{x} \mathrm{cms}^{-1}\) ?

(a) \(16 \mathrm{~T}\)

(b) \(2 \mathrm{~T}\)

(c) \(4 \mathrm{~T}\)

(d) \(32 \mathrm{~T}\)

35. The molecular velocities of two gases at the same temperature are \(\mathbf{u}_{1}\) and \(\mathbf{u}_{2}\) and their masses are \(\mathrm{m}_{1}\) and \(\mathrm{m}_{2}\) respectively. Which of the following expressions are correct?

1) \(\frac{\mathrm{m}_{1}}{\mathrm{u}_{1}^{2}}=\frac{\mathrm{m}_{2}}{\mathrm{u}_{2}^{2}}\)

2) \(\mathrm{m}_{1} \mathrm{u}_{1}=\mathrm{m}_{2} \mathrm{u}_{2}\)

3) \(\frac{m_{1}}{u_{1}}=\frac{m_{2}}{u_{2}}\)

4) \(\mathrm{m}_{1} \mathrm{u}_{1}^{2}=\mathrm{m}_{2} \mathrm{u}_{2}^{2}\)

36. Kinetic theory of gases proves

(a) only Boyle's law

(b) only Charles' law

(c) only Avogadro's law

(d) All of these

37. The root mean square velocity of an ideal gas at constant pressure varies with density \((d)\) as

(a) \(d^{2}\)

(b) \(d\)

(c) \(\sqrt{\mathrm{d}}\)

(d) \(1 / \sqrt{\mathrm{d}}\)

38. Which one of the following is the wrong assumption of kinetic theory of gases ?

(a) Momentum and energy always remain conserved.

(b) Pressure is the result of elastic collision of molecules with the container's wall.

(c) Molecules are separated by great distances compared to their sizes.

(d) All the molecules move in straight line between collision and with same velocity.

39. Consider three one-litre flasks labelled A, B and C filled with the gases \(\mathrm{NO} \mathrm{NO}_{2}\), and \(\mathrm{N}_{2} \mathrm{O}\), respectively, each at \(1 \mathrm{~atm}\) and \(273 \mathrm{~K}\). In which flask do the molecules have the highest average kinetic energy?

(a) Flask C

(b) All are the same

(c) Flask A

(d) None

40. Which of the following change is observed occurs when a substance \(\mathrm{X}\) is converted from liquid to vapour phase at the standard boiling point?

I. Potential energy of the system decreases

II. The distance between molecules increases

III. The average kinetic energy of the molecules in both phases are equal

(a) I only

(b) II only

(c) III only

(d) II and III only

41. If \(\mathrm{u}_{\mathrm{rms}}\) of a gas is \(30 \mathrm{R}^{1 / 2} \mathrm{~ms}^{-1}\) at \(27{ }^{\circ} \mathrm{C}\) then molar mass of gas is:

(a) \(0.02 \mathrm{~kg} / \mathrm{mol}\)

(b) \(0.001 \mathrm{~kg} / \mathrm{mol}\)

(c) \(0.003 \mathrm{~kg} / \mathrm{mol}\)

(d) \(1 \mathrm{~kg} / \mathrm{mol}\)

42. Consider a real gas placed in a container. If the intermolecular attractions are supposed to disappear suddenly which of the following would happen?

(a) Pressure decreases (b) Pressure increases (c) Pressure remains unchanged (d) Gas collapse

43. The pressure of a real gas is less than the pressure of an ideal gas because of :

(a) increase in number of collisions

(b) finite size of molecule

(c) increase in KE of molecules

(d) intermolecular forces of attraction

44. At what temperature the rms velocity of \(\mathrm{SO}_{2}\) be same as that of \(\mathrm{O}_{2}\) at \(303 \mathrm{~K}\) ?

(a) \(273 \mathrm{~K}\)

(b) \(606 \mathrm{~K}\)

(c) \(303 \mathrm{~K}\)

(d) \(403 \mathrm{~K}\)

45. A closed flask contains water in all its three states solid, liquid and vapour at \(0{ }^{\circ} \mathrm{C}\). In this situation, the average kinetic energy of water molecules will be

(a) equal in all the three states

(b) the greatest in vapour state

(c) the greatest in the liquid state

(d) the greatest in the solid state

\section{TOPIC 3: Van der Waal's Equation and Liquefaction of Gases}

46. The compressibility factor for \(\mathrm{H} 2\) and He is usually :

(a) \(\mathrm{Z}>1\)

(b) \(\mathrm{Z}=1\)

(c) \(\mathrm{Z}<1\)

(d) Either of these

47. It \(V\) is the volume of one molecule of gas under given conditions, the van der Waal's constant \(b\) is

(a) \(4 \mathrm{~V}\)

(b) \(\frac{4 \mathrm{~V}}{\mathrm{~N}_{0}}\)

3) \(\frac{\mathrm{N}_{0}}{4 \mathrm{~V}}\)

4) \(4 \mathrm{VN}_{0}\)

48. The units of constant ' \(a\) ' in van der Waal's equation is

(a) \(\mathrm{dm}^{6} \mathrm{~atm} \mathrm{~mol}^{-2}\)

(b) \(\mathrm{dm}^{3} \mathrm{~atm} \mathrm{~mol}^{-1}\)

(c) \(\mathrm{dm}\) atm \(\mathrm{mol}^{-1}\)

(d) atm \(\mathrm{mol}^{-1}\) 49. Maximum deviation from ideal gas is expected from :

(a) \(\mathrm{N}_{2}(\mathrm{~g})\)

(b) \(\mathrm{CH}_{4}(\mathrm{~g})\)

(c) \(\mathrm{NH}_{3}(\mathrm{~g})\)

(d) \(\mathrm{H}_{2}(\mathrm{~g})\)

50. At which one of the following temperature-pressure conditions the deviation of a gas from ideal behaviour is expected to be minimum?

(a) \(350 \mathrm{~K}\) and \(3 \mathrm{~atm}\).

(b) \(550 \mathrm{~K}\) and \(1 \mathrm{~atm}\).

(c) \(250 \mathrm{~K}\) and \(4 \mathrm{~atm}\).

(d) \(450 \mathrm{~K}\) and \(2 \mathrm{~atm}\).

51. In van der Waal's equation of state for a non-ideal gas, the term that accounts for intermolecular forces is

1) \((\mathrm{V}-\mathrm{b})\)

2)RT

3) \(\left(\mathrm{P}+\frac{\alpha}{\mathrm{V}^{2}}\right)\)

4) \((\mathrm{RT})^{-1}\)

52. In van der Waal's equation of state of the gas law, the constant ' \(b\) ' is a measure of

(a) volume occupied by the molecules

(b) intermolecular attraction

(c) intermolecular repulsions

(d) intermolecular collisions per unit volume

53. Positive deviation from ideal behaviour takes place because of

(a) molecular interaction between atoms and \(P V / n R T>1\)

(b) molecular interaction between atoms and \(P V / n R T<1\)

(c) finite size of atoms and \(P V / n R T>1\)

(d) finite size of atoms and \(P V / n R T<1\)

54. The ratio of Boyle's temperature and critical temperature for a gas is :

1) \(\frac{8}{27}\)

2) \(\frac{27}{8}\)

3) \(\frac{1}{2}\)

4) \(\frac{2}{1}\)

55. The compressibility factor for a real gas at high pressure is:

1) 1

2) \(1+\frac{\mathrm{Pb}}{\mathrm{RT}}\)

3) \(1-\frac{\mathrm{Pb}}{\mathrm{RT}}\)

4) \(1+\frac{\mathrm{RT}}{\mathrm{Pb}}\)

56. The van der Waal's constant ' \(a\) ' for four gases \(P, Q, R\) and \(S\) are 4.17, 3.59, 6.71 and \(3.8 \mathrm{~atm} \mathrm{~L}^{2} \mathrm{~mol}^{-2}\) respectively. Therefore, the ascending order of their liquefaction is

(a) \(\mathrm{R}<\mathrm{P}<\mathrm{S}<\mathrm{Q}\)

(b) \(\mathrm{Q}<\mathrm{S}<\mathrm{R}<\mathrm{P}\)

(c) \(\mathrm{Q}<\mathrm{S}<\mathrm{P}<\mathrm{R}\)

(d) \(\mathrm{R}<\mathrm{P}<\mathrm{Q}<\mathrm{S}\)

\section{TOPIC 4: Liquid State}

57. The correct order of viscosity of the following liquids will be

(a) Water \(<\) methyl alcohol \(<\) dimethyl ether \(<\) glycerol

(b) methyl alcohol < glycerol < water \(<\) dimethyl ether

(c) dimethyl ether \(<\) methyl alcohol \(<\) water \(<\) glycerol

(d) glycerol \(<\) dimethyl ether \(<\) water \(<\) methyl alcohol

58. Which among the following has lowest surface tension ?

(a) Hexane

(b) Water

(c) \(\mathrm{CH}_{3} \mathrm{OH}\)

(d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\)

59. The liquid which has the highest rate of evaporation is

(a) petrol

(b) nail-polish remover (c) water

(d) alcohol

60. A drop of oil is placed on the surface of water. Which of the following statement is correct ?

(a) It will remain on it as a sphere

(b) It will spread as a thin layer

(c) It will be partly as spherical droplets and partly as thin film

(d) It will float as a distorted drop on the water surface