chemistry MCQs - 11th class Chapter 03 Mcqs

1

According to Boyle's law, what is the relationship between the volume and pressure of a gas at constant temperature?

A

Directly proportional

B

Inversely proportional

C

No relationship

D

Exponentially related

2

The S.I. unit of pressure is expressed in which of the following?

A

atm

B

torr

C

Nm⁻²

D

psi

3

One atmospheric pressure is equal to how many torr?

A

101325

B

14.7

C

760

D

1

4

What is the phenomenon called when the sudden expansion of gases causes cooling?

A

Joule-Thomson effect

B

Avogadro's effect

C

Graham's effect

D

Dalton's effect

5

A curve plotted between pressure and volume at a constant temperature is called an:

A

Isobar

B

Isochore

C

Isotherm

D

Isotope

6

Charles's Law states that the volume of a given mass of gas is directly proportional to what, at constant pressure?

A

Number of moles

B

Pressure

C

Absolute temperature

D

Density

7

The value of absolute zero on the Celsius scale is precisely:

A

-273°C

B

-273.16°C

C

0°C

D

-100°C

8

The General Gas Equation for n moles of an ideal gas is:

A

PV = kT

B

P/T = k

C

V/T = k

D

PV = nRT

9

The value of the ideal gas constant R is 0.0821 in which units?

A

J K⁻¹ mol⁻¹

B

cal K⁻¹ mol⁻¹

C

dm³ atm K⁻¹ mol⁻¹

D

Nm K⁻¹ mol⁻¹

10

The density of an ideal gas is directly proportional to its:

A

Temperature

B

Volume

C

Molar mass

D

Gas constant R

11

Dalton's Law of Partial Pressures applies to a mixture of:

A

Reacting gases

B

Non-reacting gases

C

Ideal gases only

D

All gases

12

The partial pressure exerted by water vapours in a moist gas is called:

A

Vapour pressure

B

Absolute pressure

C

Aqueous tension

D

Saturated pressure

13

The rate of diffusion of a gas is inversely proportional to the square root of its:

A

Pressure

B

Volume

C

Temperature

D

Density

14

Which postulate of the Kinetic Molecular Theory is considered faulty for real gases at high pressure?

A

Molecules are in random motion

B

Collisions are perfectly elastic

C

Actual volume of molecules is negligible

D

Kinetic energy is proportional to temperature

15

The temperature at which a substance can exist as a liquid, above which it cannot be liquefied, is called:

A

Boiling point

B

Critical temperature

C

Absolute zero

D

Melting point

16

Linde's method for the liquefaction of gases is based on the:

A

Joule-Thomson effect

B

Doppler effect

C

Photoelectric effect

D

Compton effect

17

The van der Waals constant 'a' accounts for:

A

Effective volume of molecules

B

Intermolecular forces of attraction

C

Velocity of molecules

D

Collision frequency

18

The 'b' value in the van der Waals equation for H₂ is 0.0266 dm³ mol⁻¹. This represents the:

A

Actual volume of 1 mole

B

Volume at STP

C

Excluded volume per mole

D

Critical volume

19

Plasma was first identified by which scientist in 1879?

A

J. J. Thomson

B

William Crookes

C

John Dalton

D

Van der Waals

20

What percentage of the visible universe is estimated to be in the plasma state?

A

50%

B

75%

C

90%

D

More than 99%

21

A plot of P versus 1/V for a gas at constant temperature yields a:

A

Curve away from origin

B

Straight line parallel to P-axis

C

Straight line passing through the origin

D

Curve parallel to 1/V-axis

22

The unit 'millibar' for pressure is commonly used by:

A

Engineers

B

Chemists

C

Meteorologists

D

Physicists

23

At what temperature does the volume of a hypothetical gas become zero according to Charles's Law extrapolation?

A

0 K

B

0°C

C

100 K

D

273 K

24

The relationship °C = 5/9[°F-32] is used to convert temperature from:

A

Celsius to Kelvin

B

Fahrenheit to Celsius

C

Kelvin to Fahrenheit

D

Celsius to Fahrenheit

25

In the equation PV = 1/3 mNc², what does c² represent?

A

Speed of light

B

Mean square velocity

C

Critical velocity

D

Average velocity

26

Which of the following gases has the highest rate of diffusion?

A

O₂

B

CO₂

C

NH₃

D

Cl₂

27

What happens to the density of a gas when its temperature is increased at constant pressure?

A

Increases

B

Decreases

C

Remains the same

D

Becomes zero

28

The sum of the mole fractions of all components in a mixture is always equal to:

A

Zero

B

Unity (1)

C

Infinity

D

Depends on the gases

29

In Linde's method, air is compressed to about:

A

10 atm

B

50 atm

C

100 atm

D

200 atm

30

For an ideal gas, the compressibility factor PV/nRT is always:

A

Greater than 1

B

Less than 1

C

Equal to 1

D

Equal to zero

31

Which of the following gases shows the most ideal behavior?

A

CO₂

B

NH₃

C

SO₂

D

He

32

The units of the van der Waals constant 'a' are:

A

atm dm³ mol⁻¹

B

atm dm⁶ mol⁻²

C

dm³ mol⁻¹

D

atm mol⁻²

33

The units of the van der Waals constant 'b' are:

A

dm³ mol⁻¹

B

dm⁶ mol⁻²

C

atm dm³

D

mol dm⁻³

34

The partial pressure of oxygen in the lungs is approximately:

A

159 torr

B

116 torr

C

760 torr

D

100 torr

35

The process of spontaneous intermingling of molecules of one gas with another is called:

A

Effusion

B

Adsorption

C

Diffusion

D

Liquefaction

36

The root mean square velocity (Crms) of gas molecules is proportional to:

A

√T

B

T²

C

1/T

D

1/√T

37

Average translational kinetic energy of gas molecules is directly proportional to:

A

Pressure

B

Volume

C

Molar mass

D

Absolute temperature

38

The critical temperature of Carbon Dioxide (CO₂) is:

A

154.4 K

B

405.6 K

C

304.3 K

D

126.1 K

39

The critical pressure of Water (H₂O) is:

A

217.0 atm

B

111.5 atm

C

73.0 atm

D

49.7 atm

40

What forms in fluorescent light bulbs when electricity passes through the gas inside?

A

A vacuum

B

A solid precipitate

C

A glowing plasma

D

Liquid gas

41

According to Avogadro's law, equal volumes of all ideal gases at the same temperature and pressure contain equal:

A

Masses

B

Number of molecules

C

Densities

D

Atomic sizes

42

The volume of one mole of any ideal gas at STP (273.16 K and 1 atm) is:

A

22.414 dm³

B

1 dm³

C

100 cm³

D

224.14 dm³

43

In the kinetic equation PV = kT, the constant k is equal to:

A

2/3 N Ek

B

3/2 N Ek

C

1/2 N Ek

D

2 N Ek

44

Gases become non-ideal at:

A

High temperature and low pressure

B

High temperature and high pressure

C

Low temperature and high pressure

D

Low temperature and low pressure

45

The value of van der Waals constant 'a' is highest for which gas among the options?

A

H₂

B

N₂

C

O₂

D

Cl₂

46

The movement of gas molecules through an extremely small opening is known as:

A

Diffusion

B

Effusion

C

Osmosis

D

Brownian motion

47

At high altitudes, pilots may feel uncomfortable breathing due to:

A

Low partial pressure of oxygen

B

High partial pressure of CO₂

C

Low temperature

D

High cabin pressure

48

In the van der Waals equation, the term nb corrects for the:

A

Intermolecular attractions

B

Pressure of the gas

C

Volume occupied by gas molecules

D

Temperature of the gas

49

The fourth state of matter is:

A

Solid

B

Liquid

C

Gas

D

Plasma