Untitled Document

Question Bank No: 1

1. If r.m.s speed of gascous molecules is X cm/sec at a pressure of p bar, then r.m.s at a pressure of 2p bar and constant temperature will be

a)		X
b)		2X
c)		4X
d)		X/4

2. Which among the following gases is mass is most readily soluble in water under ordinary conditions?

a)		${NH}_{3}$
b)		${CO}_{2}$
c)		$H_{2} S$
d)		$N_{2}$

3. Which among the following has rate of effucion less than the moist air?

a)		He
b)		dry air
c)		${NH}_{3}$
d)		heavy hydrogen

4. A mixture of three gases A,B,C has a total pressure of 10 atm and total number of moles equal to 10. If partial pressure of A and B are 3.0 and 1.0 atm respectively and C has mol mass =2, then the mass of C present in the mixture is

a)		4.25g
b)		3g
c)		12g
d)		8g

5. The ratio of the root mean square velocity of $H_{2}$ at 50K and that of $O_{2}$ at 800K is

a)		4
b)		2
c)		1
d)		$\frac{1}{4}$

6. In a closed room of 1000 $m^{3}$ , a perfume bottle is opened up. The whole room after some time devolps smell of perfume. This is due to which property of gases

a)		Viscosity
b)		density
c)		diffusion
d)		none of these

7. Equal masses of methane and hydrogen are mixed in an empty container at $25^{0} C$ .The fraction of total pressure exerted by hydrogen is

a)		$\frac{1}{2}$
b)		$\frac{8}{9}$
c)		$\frac{1}{16}$
d)		$\frac{4}{9}$

8. Air contains 79 $% N_{2}$ and 21 $% O_{2}$ by volume.If pressure is 750mm of Hg, the partial pressure of oxygen is

a)		175 mm of Hg
b)		157.5 mm of Hg
c)		320 mm of Hg
d)		250 mm of Hg

9. The gases A and B have molecular masses 64 and 100 respectively. If A effuses out of porous plug at a rate of 15 mL $s^{- 1}$ , the rate of effusion of other gas under similar conditions will be

a)		12 mL $s^{- 1}$
b)		6mL $s^{- 1}$
c)		24 mL $s^{- 1}$
d)		10 mL $s^{- 1}$

10. Which of the following mixture of gases at room temperature follow dalton's law of partial pressure?

a)		${NH}_{3}, HCL$
b)		$H_{2}, O_{2}$
c)		NO, $O_{2}$
d)		All the above

11. A Boyle's temperature, for a considerable range of pressure, the value of Z is

a)		=0
b)		$> 1$
c)		=1
d)		$< 1$

12. Under similar conditions which of the following gas will diffuse four times as quick as oxygen?

a)		He
b)		$H_{2}$
c)		$N_{2}$
d)		$D_{2}$

13. Which one of the following samples contain largest number of atoms?

a)		1 g of $C_{2} H_{6}$
b)		1 g of $O_{3}$
c)		1 g of $O_{2}$
d)		1 g of He

14. Which graph will not be straight line for ideal gas?

a)		PV $υ s$ P
b)		P/T $υ s$ T
c)		P $υ s$ T
d)		V $υ s$ T

15. A gas was compressed to half of its volume (V) at $27^{0} C$ . To what temperature should it be heated so that its volume increases to 2V?

a)		600K
b)		$54^{0} C$
c)		$927^{0} C$
d)		$1200^{0} C$

16. Which of the given sets of temperature and pressure will cause a gas to exhibit the greatest deviation from ideal gas behaviour?

a)		$100^{0} C$ and 4 atm
b)		$100^{0} C$ and 2 atm
c)		- $100^{0} C$ and 4 atm
d)		$0^{0} C$ and 2 atm

17. The r.m.s velocity of a gas depends upon

a)		Temperature only
b)		molecular mass only
c)		temperature and molecular mass of gas
d)		none of these

18. A gas is initially at 1 bar pressure. To compress it to $\frac{1}{4}$ th of its initial volume at constant temperature, the pressure to be applied is

a)		1 bar
b)		2 bar
c)		4 bar
d)		$\frac{1}{4}$ bar

19. The volume of 2.8 g of carbon monoxide at $27^{0} C$ and 0.821 atm pressure is R=0.0821 lit. atm. ${mol}^{- 1} K^{- 1}$

a)		30 L
b)		3 L
c)		0.3 L
d)		1.5 L

20. A gaseous mixture of three gases A,B and C has a pressure of 10 atm. The total number of moles of all the gases is 10. If the partial pressures of A and B are 3.0 and 1.0 atm respectively and if 'C' has mol.wt. of 2.0, what is the weight of 'C' in g present in the mixture

a)		8
b)		12
c)		3
d)		6

21. If the volume of 2 moles of an ideal gas at 540K is 44.8litre then its pressure will be

a)		1 atmosphere
b)		2 atmosphere
c)		3 atmosphere
d)		4 atmosphere

22. The compressibility factor of an ideal gas is

a)		0
b)		1
c)		2
d)		4

23. The density of a gas at $27^{0} C$ and 1 atm is d. Pressure remaining constant, at which of the following temperatures will its density become 0.75d?

a)		$20^{0} C$
b)		$30^{0} C$
c)		400 K
d)		300 K

24. One litre of a gas weighs 2 g at 300K 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?

a)		450 K
b)		600 K
c)		800 K
d)		900 K

25. The correct value of the gas constant R is close to

a)		0.082 litre-atm $K^{- 1} {mol}^{- 1}$
b)		0.082 litre- ${atm}^{- 1} K mol$
c)		0.082 litre-atm K
d)		0.082 litre - ${atm}^{- 1} {K mol}^{- 1}$

26. The total pressure exerted by a number of non reacting gases is equal to the sum of partial pressure of the gases under the same conditions is known as

a)		Boyle's law
b)		Charle's law
c)		Avogadro's law
d)		Dalton's law

27. The number of molecules in 4.25g of ammonia are approximately

a)		0.5 $\times 10^{23}$
b)		1.5 $\times 10^{23}$
c)		2.5 $\times 10^{23}$
d)		3.5 $\times 10^{23}$

28. Pure hydrogen sulphide gas is stored in a tank of 100L capacity at $20^{0} C$ and 2 atm pressure. The mass of gas in gram is

a)		34g
b)		340g
c)		283.0g
d)		28.3g

29. If $V_{0}$ is the volume of X of an ideal gas at 273K then its volume at $20^{0} C$ will be

a)		20 $V_{0}$
b)		$V_{0} \times \frac{20}{273}$
c)		$\frac{293 V_{0}}{273}$
d)		$V_{0} + \frac{20}{273}$

30. A 0.5 d $m^{3}$ flask contains gas A(Mol.mass X) and a 1 d $m^{3}$ flask contains a gas B(Mol. mass 2X) If density of gas A is 3 g d $m^{- 3}$ and that of B is 1.5 g d $m^{- 3}$ , the ratio of the pressure $P_{A} : P_{B} is$

a)		4:1
b)		3:1
c)		2:1
d)		1:2

31. An ideal gas at 1 atm is heated from $0^{0} C$ to 373 k. If its initial volume is 5.46L, the final volume would be

a)		7.46 L
b)		1.865L
c)		5.46L
d)		6.0L

32. A pressure of 0.101325 bar when expressed in atmospheres represents

a)		0.01 atm
b)		1 atm
c)		0.1 atm
d)		10 atm

33. By what factor does water expand when converted into vapour at $100^{0} C$ at 1 atm pressure. The density of liquid water at $100^{0} C$ and 1 atm is 0.96 gc $m^{- 3}$

a)		815
b)		2000
c)		1630
d)		500

34. The mass of CO that can be mixed with 70g of dry nitrogen so that both have same partial pressure is

a)		70 g
b)		$\frac{70}{28} g$
c)		110 g
d)		28 $\times 70 g$

35. The compressibility of gas is less than unity at STP therefore

a)		$V_{m} > 22.4 L$
b)		$V_{m} < 22.4 L$
c)		$V_{m} = 22.4 L$
d)		$V_{m} = 44.8 L$

36. A gaseous mixture containing 2 g $H_{2}$ , 8 g He, 22 g C $O_{2}$ and 8 g $O_{2}$ is enclosed in a vessel. The gas with highest partial pressure is

a)		He
b)		$H_{2}$
c)		${CO}_{2}$
d)		$O_{2}$

37. 1000 ml of a gas A at 600 torr and 500 ml of gas b at 800 torr are placed in a 2L flask. The final pressure in atmosphere is

a)		2000
b)		1000
c)		500
d)		0.657

38. Which among the following sample of gases contain Avogadro number of atoms at S.T.P?

a)		2 g of Helium
b)		11.2L of carbon monoxide
c)		11.2 L of sulphur dioxide
d)		1 mol of Phosphine

39. Liquefaction of gases cannot be achieved by

a)		cooling
b)		compressing the gas at all temperatures
c)		compressing the gas as well as cooling
d)		compressing the gas below critical temperature

40. The Van der Waal's equation for n moles of a real gas will be

a)		$(P - \frac{an}{V^{2}}) (V + nb) = nRT$
b)		$(P + \frac{an}{V^{2}}) (V + nb) = nRT$
c)		$(P + \frac{{an}^{2}}{V}) (V - nb) = Δ nRT$
d)		$(P + \frac{{an}^{2}}{V^{2}}) (V - nb) = nRT$

41. The density of $N_{2}$ will be highest at

a)		S.T.P
b)		273 K, 2atm
c)		545 K, 1 atm
d)		500 K, 1.5 atm

42. A gas initially at 1 atm pressure. To compress it to $\frac{1}{4} th$ of its initial volume at constant temperature, the pressure to be applied is

a)		1 atm
b)		2 atm
c)		4 atm
d)		$\frac{1}{4} atm$

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

a)		Boyle's law
b)		Charle's law
c)		Avogadro's law
d)		Dalton's law

44. The van der Waal equation of state reduces itself to the ideal gas equation at

a)		high pressure and low temperature
b)		low pressure and low temperature
c)		low pressure and high temperature
d)		high pressure and high temperature

45. In a mole of water vapour at STP, the volume actually occupied or taken up by the molecules (i,e., Avogadro number $\times$ the volume of one molecule) is

a)		zero
b)		less than 0.1% of the volume of 22.4 litres
c)		about 10% of the volume of the container of 22.4 litres
d)		between 10% to 2% of 22.4 litres

46. Gas deviates from ideal gas nature because molecules

a)		are colourless
b)		attract each other
c)		contain covalent bond
d)		show Brownian movement

47. An ideal gas obeying kinetic gas equation can be liquefied if

a)		its temperature is more than critical temperature
b)		its pressure is more than critical pressure
c)		its pressure is more than critical pressure but temperature is less than critical temperature
d)		It cannot be liquefied at any value of P and T

48. The number of moles of $H_{2}$ in 0.224 L of hydrogen gas at STP(273 K, 1atm. assuming ideal gas behaviour is

a)		1
b)		0.1
c)		0.01
d)		0.001

49. The density of methane at 2.0 atmosphere pressure at 2 $7^{\circ} C$ is

a)		0.13g $L^{- 1}$
b)		0.26g $L^{- 1}$
c)		1.30g $L^{- 1}$
d)		26.0g $L^{- 1}$

50. Two separate bulbs contain ideal gases A and B. The density of A is twice as that of gas B. The molecular mass of gas A is half as that of B. If two gases are at same temperature, the ratio of the pressure of A to that of B is

a)		2
b)		$\frac{1}{2}$
c)		4
d)		$\frac{1}{4}$