PPSC Lecturer Chemistry Past Paper 2015 Page 4

PPSC Lecturer Chemistry Past Paper Dated: 2015

61- A gas has a volume of 2 liters at STP at constant pressure. The new volume is 4 liters at which temperature?

A. 0°C

B. 50°C

C. 100°C

D. 273°C

View Answer

Answer : D. 273°C

Description

62- The difference between crystalloids and colloids is:

A. Density

B. Solubility

C. Color

D. Particle size

View Answer

Answer : D. Particle size

Description

63- The gas which shows deviation from ideal behavior is:

A. Helium

B. Hydrogen

C. Ammonia

D. Trichloromethane

View Answer

Answer : C. Ammonia

Description

64- A substance shows scattering of light but can pass through ordinary filter paper. It is:

A. Colloids

B. Suspension

C. True solution

D. None of these

View Answer

Answer : A. Colloids

Description

65- In the lime kiln, CaCO₃ → CaO + CO₂ proceeds to completion because:

A. CO₂ escapes

B. CaO is removed

C. Low temperature

D. High pressure

View Answer

Answer : A. CO₂ escapes

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66- Which equation is NOT affected by change in pressure?

A. ½N₂ + ½O₂ → NO

B. P₂O₅ → P₂O + O₂

C. N₂ + 3H₂ → 2NH₃

D. None of these

View Answer

Answer : A. ½N₂ + ½O₂ → NO

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67- A reaction approaches farthest completion when:

A. K = 10²

B. K = 10¹

C. K = 10⁰

D. K = 10⁻²

View Answer

Answer : A. K = 10²

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68- An isothermal system is one in which:

A. V = 0

B. E = 0

C. ΔT = 0

D. ΔE = W

View Answer

Answer : C. ΔT = 0

Description

69- Temperature of the system decreases in:

A. Adiabatic expansion

B. Adiabatic compression

C. Isothermal expansion

D. Isothermal compression

View Answer

Answer : A. Adiabatic expansion

Description

70- A system in which no change in temperature occurs is:

A. Isochoric

B. Isobaric

C. Isothermal

D. Adiabatic

View Answer

Answer : C. Isothermal

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71- The cyclic structure of benzene was given by:

A. Kekulé

B. Dobereiner

C. Newlands

D. Mendeleev

View Answer

Answer : A. Kekulé

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72- Which is least soluble in water?

A. Ethanol

B. Benzene

C. Benzoic acid

D. Phenol

View Answer

Answer : B. Benzene

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73- Heterogeneous catalysis is based on:

A. Desorption

B. Sorption

C. Absorption

D. Adsorption

View Answer

Answer : D. Adsorption

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74- The entropy of the universe is:

A. Always increasing

B. Always decreasing

C. Constant

D. Zero

View Answer

Answer : A. Always increasing

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75- Which indicator is NOT used in a conical flask?

A. Self indicator

B. External indicator

C. Internal indicator

D. Mixed indicator

View Answer

Answer : B. External indicator

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76- Toluene is prepared from benzene by:

A. Wurtz reaction

B. Cannizzaro reaction

C. Perkin reaction

D. Friedel-Crafts alkylation

View Answer

Answer : D. Friedel-Crafts alkylation

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77- The catalyst used in Friedel-Crafts alkylation is:

A. BF₃

B. AlCl₃

C. FeCl₃

D. ZnCl₂

View Answer

Answer : B. AlCl₃

Description

78- The order of a reaction is:

A. Always 1

B. Always 2

C. Can be determined from the equation

D. Can be determined from experiment

View Answer

Answer : D. Can be determined from experiment

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79- The oxidation number of P in KH₂PO₂ is:

A. +1

B. +2

C. +3

D. +5

View Answer

Answer : A. +1

Description

80- Molten KCl conducts electricity because of:

A. Free ions

B. Free electrons

C. Both A and B

D. None of these

View Answer

Answer : A. Free ions

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