(Introduction Upto Dalton’s Law)

(Gases)

1. Which of the following states that the average K.E of molecules of an

ideal gas 1s directly proportional to absolute temperature according to

KMT?

A. Charles’s law B. Boyle’s law

C. Dalton’s law D. Gay Lussac’s law

2. How should be the conditions changed to prevent the volume of a given gas from expanding when its mass 1s increased?

A. Temperature is decreased and pressure is increased

B. Temperature is increased and pressure 1s increased

C. Temperature and pressure both are decreased

D. Temperature and pressure both are increased

3. Which of the following is most ideal gas at STP?

A. SO; B. HCl

C. CO, D. H;

4. The volume of the given mass of a gas increases or decreases by 1/273 of

its original volume at 0°C for every rise or fall in its temperature.

A. 1°C B. 25°C

C. 10°C D. 273K

5. At which temperature the volume of a gas becomes twice of what it 1s at 0°C keeping the pressure constant:

A. 546°C B. 200°C

C. 546K D. 273K

6. The rate of diffusion of the gases NHz, SO», Cl; and COz 1s in the order of:

A. NH;> SO>,> ClL,> CO»

B. NH3> CO2> SO, > Cl,

C. Clb>S0O,> CO>> NHs3

D. NH;> CO» > Cl > SO»

7. The number of molecules in one dm?’ of water is close to:

A. 6.02 x 10%/22.414 B. 12.04 x 10%3/22.414

C. 18 x 10%3/22.414 D. 55.6 x 6.02 x 10>

8. Which graph represents Boyle’s law at constant temperature?

9. The isotherms of CO; change their position in the graph by changing the temperature in such a way that:

A. The curves come close to the axis by increasing temperature

B. The curves go away from the axis by increasing the temperature

C. The curves are converted into straight line at high temperature

D. The curves become discontinuous at 31.5°C

10. The deviation of a gas from ideal gas behaviour 1s maximum at:

A. -10°C and 5.0atm B. —10°C and 2.0atm

C. 100°C and 2.0atm D. 0°C and 2.0atm

11. Equal masses of methane and oxygen are mixed in an empty container

at 20°C. The fraction of total pressure exerted by oxygen will be:

A. 1/3 B. 8/9

C. 1/9 D. 16/17

12. Critical temperature of argon 1s low. The reason 1s that:

A. It1s mono atomic gas

B. It contains four lone pairs

C. Ithas a small size

D. It has low polarizability

13. A mixture of 2 moles of Hy and 1 mole of O,, has the total pressure 200 torr, the partial pressure of O; will be:

A. 88.88torr B. 77.77torr

C. 66.67torr D. 44 44torr

14. Which of the following gases has greater value of critical temperature?

A. NH; B. O;

C. CO; D. CH4

15. Which of the following is the mixture of non-reacting gases?

A. Hxand Og; B. He and Ne

C. NHs and HCI D. CHs and N»

16. Which one of the following expression represent the Avogadro’s law?

A. V =RnT/P (When T and n are constant)

B. V=RnT/P (When T and P are constant)

C. V =RnT/P (When P and n are constant)

D. V=RP/nT (When T, P and n are constant)

17. When a compressed gas 1s allowed to expand into a region of low pressure it causes cooling. It 1s the statement of:

A. Stark effect B. Joule Thomson’s effect

C. Zeeman effect D. Screening effect

18. latm 1s equal to:

A. 760torr B. 760mm of Hg

C. 101325Nm 2 D. All of these

19. Which of the following gases has greater rate of diffusion?

A. He B. H;

C. CO; D. N»

20. Density of gas is more comfortably expressed in:

A. gem? B. gmol™

C. gdm? D. kgdm™

21. Which of the following pairs of gases have same number of molecules at S.T.P?

A. 100cm?’ N>Hz and 100cm? O;

B. 200cm’® CO and 200cm?® N;

C. 50cm’ CO» and 50cm’ N,O

D. All of these

22. In a mixture of two components A and B. If mole fraction of A is 0.25 and total pressure is 4atm then the partial pressure of B component will

be atm.

A. 1 B. 2

C.3 D. 4

23. According to Boyle’s law which parameters give a straight line parallel to x-axis when we plot a graph between:

A. Pand PV B.Pand V

C.Pand 1/V D.VandT

24. If absolute temperature is doubled and pressure 1s reduced to one half

the volume of gas will:

A. Reduce to U4 B. Double

C. Increase 4 times D. Remains same

25. The most abundant state of matter around us is:

A. Gas B. Liquid

C. Solid D. Plasma

(Gases)

(Diffusion and Effusion upto Plasma)

1. Which of the following equations is used for real gases?

A. PV =nRT

B. PV = “mc?

C PV, _ P,V,

oo I, n%a

D. {Pob + ——] (Vyessel -nb) =nRT v2

• Which of the following equations 1s applicable to an ideal gas?

A.V =dRT/M B. P=MRT

C.P=dRT/M D. P=nRT

3. Gases deviate from ideal gas behaviour at high pressure. Which of the following 1s correct for non- ideality?

1. At high pressure, the collision between the gas molecules 1s increased manifold
2. At high pressure, the volume of the gas becomes insignificant
3. At high pressure, the intermolecular attraction becomes significant

4. Equal volumes of all the 1deal gases at the same temperature and pressure contain equal number of molecules. This 1s in accordance to:

A. Boyle’s law B. Charles’s law

C. Avogadro’s law D. Dalton’s law

• The molar volume of CO» is maximum at:

A. S.T.P (25°C and latm) B. 127°C and 1atm

C. 0°C and 2atm D. 273°C and 2atm

6. The volume of helium gas will be 44.8dm? at:

A. 100°C and latm B. 25°C and 0.25atm

C. 273k and latm D. 546k and latm

7. Which of the following mixture of gases does not obey Dalton’s law of partial pressure?

A. Oz and CO, B. NHs; and HCI

C. No» and O» D. Ch and SO»

8. The compressibility factor 1s:

A. PV

B. T

C. RV

9. Which one of the following gas shows maximum non ideal behaviour?

A. He B. Hy

C. CO; D. N»

10. Gases are bubbled through liquids because of:

A. Low density

B. High volume

C. Greater velocity

D. Lesser intermolecular forces

11. What will be the mass of 10?° molecules of CO; at STP?

A.7.3×10°g B.7.9x 107g

C.32x 102% D. 42x 10%

12. The value of general gas constant R in SI units 1s:

A. 8.3143kJ k”mol™! B. 8.3143Nm k”mol!

C. 0.0821dm? atm k™’mol™! D. 62.4dm? torr k”mol’!

13. A gas was compressed to half of its volume at 303K to what temperature, it should be heated, so that its original volume is obtained at constant pressure:

A. 303K B. 230K

C. 330K D. 606K

14. “a” and “b” are called van der waal’s constants. The standard unit of a 1S:

A. atm dm’ mol? B. Nm™! mol?

C. atm dm° mol D. atm™ mol?

15. Under what conditions of temperature and pressure, a real gas will behave like an ideal gas?

Options | Temperature Pressure

A. Low Low

B. High Low

C. Low High

D High High

16. The gas laws can be summarized in the ideal gas equation PV = nRT which of the following statements 1s / are incorrect?

A. One mole of an ideal gas occupies the same volume under the same conditions of temperature and pressure

B. The density of an ideal gas at constant pressure is proportional to temperature

C. Volume of a given mass of a gas increases two times 1f temperature is raised from 25°C to 50°C at constant pressure

D. Both A and B

17. The value of universal gas constant R depends on:

A. Temperature of gas

B. Volume of gas

C. Number of moles of gas

D. Units of volume and pressure

18. A gas ‘A’ diffuses three times faster than another gas ‘B’. the ratio of densities between gas A and B 1s:

A. 1:3 B. 1:9

C. 3:1 D. 1:12

19. What 1s the correct expression for the partial pressure of na moles of a gas 1n a mixture of gases?

A. Pa = (na + ny) Py B. Pa = (n¢-na)Py

C. Pa = naP;: D. Pa = (na/my) Py

20. One mole of a gas reacts with exactly five moles of oxygen, forming carbon dioxide and water the gas 1s?

A. Ethane B. Propane

C. Methane D. Butane

21.If the values of van der waal’s constant are zero for certain gas, than gas will behave like an:

A. Ideal gas B. Non ideal gas

C. Real gas D. Liquefied gas

22. Which graph is not correct for fixed mass of an ideal gas at constant temperature?

A. wy

B. iN

23. Which of the following methods 1s used for the liquefaction of gases:

A. Faraday’s method B. Lind’s method

C. Claud’s method D. All of these

24. Mark the incorrect statement:

A. General gas equation …. PV =nRT

B. Kinetic gas equation …. PV = ~mNC :

C. Van der Waal’s gas equation …. (P, + ==) (V_free nb)=nRT\Y Ve V

D. Charle’s law equation … — = —1 2

25. The rate of diffusion of hydrogen is three times than that of an unknown gas at same temperature and pressure, then the molar mass of unknown gas will be:

A. 18 B. 16

C. 32 D. 27