Blogger Widgets APEX INSTITUTE : CHEMISTRY PRACTICE PROBLEMS FOR IIT Main

Friday, September 13, 2013

CHEMISTRY PRACTICE PROBLEMS FOR IIT Main

1. Which one of the following statements is not correct about the three states of matter i.e. solid, liquid and gaseous
(a) Molecules of a solid possess least energy whereas those of a gas possess highest energy
(b) The density of solid is highest whereas that of gases is lowest
(c) Gases like liquids possess definite volumes
(d) Molecules of a solid possess vibratory motion
2. The temperature and pressure at which ice, liquid water and water vapour can exist together are
(a) (b) (c) (d)
3. Which of the following is true about gaseous state
(a) Thermal energy = Molecular attraction (b) Thermal energy >> Molecular attraction
(c) Thermal energy << Molecular attraction (d) Molecular forces >> Those in liquids
4. Kinetic energy of molecules is highest in
(a) Gases (b) Solids (c) Liquids (d) Solutions
5. Which of the following statement is correct
(a) In all the three states the molecules possess random translational motion
(b) Gases cannot be converted into solids without passing through liquid state
(c) One of the common property of liquids and gases is viscosity
(d) According to Boyle's law V/P is constant at constant T
6. Volume occupied by a gas at one atmospheric pressure and   is V mL. Its volume at 273 K will be [Bihar MADT 1982]
(a) V ml (b) V/2 ml (c) 2 V (d) None of these
7. Which one of the following statements is wrong for gases [CBSE PMT 1999]
(a) Gases do not have a definite shape and volume
(b) Volume of the gas is equal to the volume of the container confining the gas
(c) Confined gas exerts uniform pressure on the walls of its container in all directions
(d) Mass of the gas cannot be determined by weighing a container in which it is enclosed
8. Two separate bulbs contain ideal gases A and B. The density of gas A is twice that of gas B. The molecular mass of A is half that of gas B. The two gases are at the same temperature. The ratio of the pressure of A to that of gas B is   [BHU 1994]
(a) 2 (b) 1/2 (c) 4 (d) 1/4
9. 16 g of oxygen and 3 g of hydrogen are mixed and kept at 760 mm pressure and  . The total volume occupied by the mixture will be nearly [Vellore CMC 1991]
(a) 22.4 litres (b) 33.6 litres (c) 448 litres (d) 44800 ml
10. Pure hydrogen sulphide is stored in a tank of 100 litre capacity at   and 2 atm pressure. The mass of the gas will be [CPMT 1989]
(a) 34 g (b) 340 g (c) 282.4 g (d) 28.24 g
11. At N.T.P. the volume of a gas is found to be 273 ml. What will be the volume of this gas at 600 mm Hg and   [CPMT 1992]
(a) 391.8 mL (b) 380 ml (c) 691.6 ml (d) 750 ml
12. One litre of a gas weighs 2 g at 300 K and 1 atm pressure. If the pressure is made 0.75 atm, at which of the following temperatures will one litre of the same gas weigh one gram [CBSE PMT 1992]
(a) 450 K (b) 600 K (c) 800 K (d) 900 K
13. A wheather balloon filled with hydrogen at 1 atm and   has volume equal to 12000 litres. On ascending it reaches a place where the temperature is   and pressure is 0.5 atm. The volume of the balloon is [CBSE PMT 1991]
(a) 24000 litres (b) 20000 litres (c) 10000 litres (d) 12000 litres
14. The density of a gas at   and 1 atm is d. Pressure remaining constant at which of the following temperatures will its density become 0.75 d [CBSE PMT 1992]
(a) (b) (c) 400 K (d) 300 K
15. A sample of gas occupies 100 ml at   and 740 mm pressure. When its volume is changed to 80 ml at 740 mm pressure, the temperature of the gas will be [Vellore CMC 1991]
(a) (b) (c) (d)
16. In an experiment during the analysis of a carbon compound, 145   of   was collected at 760 mm Hg pressure and   temperature. The mass of   is nearly [MLNR 1987]
(a) 10 g (b) 12 g (c) 24 g (d) 6 g
17. The molecular weight of a gas which diffuses through a porous plug at 1/6th of the speed of hydrogen under identical conditions is
[EAMCET 1990]
(a) 27 (b) 72 (c) 36 (d) 48
18. Molecular weight of a gas that diffuses twice as rapidly as the gas with molecular weight 64 is [EAMCET 1994]
(a) 16 (b) 8 (c) 64 (d) 6.4
19. The densities of hydrogen and oxygen are 0.09 and 1.44 g  . If the rate of diffusion of hydrogen is 1 then that of oxygen in the same units will be [Raj. PMT 1994]
(a) 4 (b) 1/4 (c) 16 (d) 1/16
20. If rate of diffusion of A is 5 times that of B, what will be the density ratio of A and B [AFMC 1994]
(a) 1/25 (b) 1/5 (c) 25 (d) 4
21. 50 ml of hydrogen diffuses out through a small hole from a vessel in 20 minutes. The time needed for 40 ml of oxygen to diffuse out is
[CBSE PMT 1994]
(a) 12 min (b) 64 min (c) 8 min (d) 32 min
22. The densities of two gases are in the ratio of 1 : 16. The ratio of their rates of diffusion is [CPMT 1995]
(a) 16 : 1 (b) 4 : 1 (c) 1 : 4 (d) 1 : 16
23. If 4 g of oxygen diffuse through a very narrow hole, how much hydrogen would have diffused under identical conditions [CPMT 1971]
(a) 16 g (b) 1 g (c) 1/4 g (d) 64 g
24. A gas diffuse at a rate which is twice that of another gas B. The ratio of molecular weights of A to B is [EAMCET 1986]
(a) 1.0 (b) 0.75 (c) 0.50 (d) 0.25
25. Two grams of hydrogen diffuse from a container in 10 minutes. How many grams of oxygen would diffuse through the same container in the same time under similar conditions [MLNR 1980]
(a) 0.5 g (b) 4 g (c) 6 g (d) 8 g
26. Postulate of kinetic theory is [EAMCET 1980]
(a) Atom is indivisible (b) Gases combine in a simple ratio
(c) There is no influence of gravity on the molecules of a gas (d) None of the above
27. According to kinetic theory of gases, [EAMCET 1980]
(a) There are intermolecular attractions (b) Molecules have considerable volume
(c) No intermolecular attractions (d) The velocity of molecules decreases after each collision
28. In deriving the kinetic gas equation, use is made of the root mean square velocity of the molecules because it is [Bihar MADT 1980]
(a) The average velocity of the molecules
(b) The most probable velocity of the molecules
(c) The square root of the average square velocity of the molecules
(d) The most accurate form in which velocity can be used in these calculations
29. Kinetic energy of a gas depends upon its [Bihar MADT 1982]
(a) Molecular mass (b) Atomic mass (c) Equivalent mass (d) None of these
30. The kinetic theory of gases perdicts that total kinetic energy of a gaseous assembly depends on [NCERT 1984]
(a) Pressure of the gas (b) Temperature of the gas
(c) Volume of the gas (d) Pressure, volume and temperature of the gas
31. According to kinetic theory of gases, the energy per mole of a gas is equal to [EAMCET 1985]
(a) 1.5 RT (b) RT (c) 0.5 RT (d) 2.5 RT
32. Helium atom is two times heavier than a hydrogen molecule at 298 K, the average kinetic energy of helium is [IIT 1982]
(a) Two times that of a hydrogen molecule (b) Same as that of a hydrogen molecule
(c) Four times that of a hydrogen molecule (d) Half that of a hydrogen molecule
33. Which of the following is valid at absolute zero [Pb. CET 1985]
(a) Kinetic energy of the gas becomes zero but the molecular motion does not become zero
(b) Kinetic energy of the gas becomes zero and molecular motion also becomes zero
(c) Kinetic energy of the gas decreases but does not become zero
(d) None of the above
34. If a gas is expanded at constant temperature [IIT 1986]
(a) The pressure increases (b) The kinetic energy of the molecules remains the same
(c) The kinetic energy of the molecules decreases (d) The number of molecules of the gas increases
35. The average K.E. of an ideal gas in calories per mole is approximately equal to [EAMCET 1989]
(a) Three times the absolute temperature (b) Absolute temperature
(c) Two times the absolute temperature (d) 1.5 times the absolute temperature
36. According to kinetic theory of gases, for a diatomic molecule [MLNR 1991]
(a) The pressure exerted by the gas is proportional to the mean velocity of the molecules
(b) The pressure exerted by the gas is proportional to the root mean square velocity of the molecules
(c) The root mean square velocity is inversely proportional to the temperature
(d) The mean translational kinetic energy of the molecules is proportional to the absolute temperature
37. At STP, 0.50 mol   gas and 1.0 mol He gas [CBSE PMT 1993, 2000]
(a) Have equal average kinetic energies (b) Have equal molecular speeds
(c) Occupy equal volumes (d) Have equal effusion rates
38. When an ideal gas undergoes unrestrained expansion, no cooling occurs because the molecules [IIT 1984, 89]
(a) Are above the inversion temperature (b) Exert no attractive force on each other
(c) Do work equal to loss in kinetic energy (d) Collide without loss of energy
39. A gas is said to behave like an ideal gas when the relation  . When do you expect a real gas to behave like an ideal gas [IIT 1999; CBSE PMT 1990; CPMT 1991]
(a) When the temperature is low (b) When both the temperature and pressure are low
(c) When both the temperature and pressure are high (d) When the temperature is high and pressure is low
40. A real gas most closely approaches the behaviour of an ideal gas at [KCET 1992]
(a) 15 atm and 200 K (b) 1 atm and 273 K (c) 0.5 atm and 500 K (d) 15 atm and 500 K
41. The temperature at which real gases obey the ideal gas laws over a wide range of pressure is called [AFMC 1993; IIT 1981, 94]
(a) Critical temperature (b) Boyle temperature (c) Inversion temperature (d) Reduced temperature
42. Which set of conditions  represents easiest way to liquefy a gas [NCERT 1983]
(a) Low temperature and high pressure (b) High temperature and low pressure
(c) Low temperature and low pressure (d) High temperature and high pressure
43. Adiabatic demagnetisation is a technique used for [BHU 1984]
(a) Adiabatic expansion of a gas (b) Production of low temperature
(c) Production of high temperature (d) None
44. An ideal gas can't be liquefied because [CBSE PMT 1992]
(a) Its critical temperature is always above   (b) Its molecules are relatively smaller in size
(c) It solidifies before becoming a liquid (d) Forces operative between its molecules are negligible
45. However great the pressure, a gas cannot be liquefied above its
(a) Boyle temperature (b) Inversion temperature (c) Critical temperature (d) Room temperature
46. A gas can be easily liquefied
(a) When its inversion temperature equals the Boyle temperature
(b) Under adiabatic expansion
(c) Under pressure when it is cooled to below the critical temperature
(d) At low pressure and above the critical temperature
47. Which of the following is correct for critical temperature
(a) It is the highest temperature at which liquid and vapour can coexist
(b) Beyond the critical temperature, there is no distinction between the two phases and a gas cannot be liquefied by compression
(c) At critical temperature   the surface tension of the system is zero
(d) At critical temperature the gas and the liquid phases have different critical densities
48. A gas has a density of 2.68   at stp. Identify the gas
(a) (b) Kr (c) COS (d)
49. Who among the following scientists has not done any important work on gases [Bihar MADT 1980]
(a) Boyle (b) Charles (c) Avogadro (d) Faraday
50. The ratio   for inert gases is [AFMC 1990]
(a) 1.33 (b) 1.66 (c) 2.13 (d) 1.99
51. The density of neon will be highest at [CBSE PMT 1990]
(a) S.T.P. (b) (c) (d)
52. Absolute zero is defined as the temperature [CBSE PMT 1990]
(a) At which all molecular motion ceases (b) At which liquid helium boils
(c) At which ether boils (d) All of the above
53. Five grams each of the following gases at   and 750 mm pressure are taken. Which of them will have the least volume [MNR 1991]
(a) HF (b) HCl (c) HBr (d) HI
54. Which of the following is most polarised among noble gases [AFMC 1994]
(a) He (b) Xe (c) Kr (d) Rn
55. Dimensions of pressure are the same as that of [CBSE PMT 1995]
(a) Energy (b) Force (c) Energy per unit volume (d) Force per unit volume

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