Assertion: HC= C- is more stable than H2C ≡CH-Reason : HC&e

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 Multiple Choice QuestionsMultiple Choice Questions

261.

The use of CCl4 as fire extinguisher depends on the fact that :

  • it is an inorganic compound

  • it is an organic compound

  • its vapour is much heavier than air and non-combustible

  • it is a compound of chlorine


262.

Tertiary alkyl halides are practically inert towards substitution by SN2 mechanism because of :

  • steric hindrance

  • inductive effect

  • instability

  • insolubility


263.

Chloroform , on exposing to air and sunlight produce :

  • chloropicrin

  • phosgene

  • carbon tetrachloride

  • benzene


264.

Which of the following does not give nitroalkane?

  • CH3-N(CH3)-CH3 KMnO4

  • C2H5alc. AgNO2

  • CH3 - CH3 Fuming HNO3

  • Both (a) and (b)


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265.

Which of the following is true for an ideal solution?

  • H(mix) = 0

  • S(mix) = 0

  • G(mix) = 0

  • None of these


266.

Boiling point of benzene is 353.23 K. When 1.8 g of non-volatile solute is dissolved in 90 g of benzene. Then boiling point is raised to 354.11 K. Given Kb (benzene) = 2.5 kg mol-1. The molecular mass of non-volatile substance is

  • 58 g mol-1

  • 120 g mol-1

  • 116 g mol-1

  • 60 g mol-1


267.

But-1-ene H3O(CH3COO)2?

The product in the above reaction is

  • CH3CH2CH2CH2OH

  • CH3CH2CH(OH)CH3

  • CH2=CH2CH(OH)-CH3

  • CH3-CH=C(OH)-CH3


268.

Assertion : Aryl sulphunic acid gives phenol or reacting with NaOH at high temperature.

Reason : This reaction is electrophilic substitution reaction.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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269.

Assertion: HC= C- is more stable than H2C CH-
Reason : HC C- has more s-character than HC= CH-

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


A.

If both assertion and reason are true and reason is the correct explanation of assertion.

HCC- has 50% s-character and H2C=CH- has 33% s-character. Stability ofcarbanions increases with an increase in the s-character at the carbanion. So HCC- is more stable than H2C= CH-.


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270.

Which of the following reaction follows SN1 mechanism ?

  • (CH3)2C-CH2Cl + CH2OK

  • (CH3)2C-CH2Cl + HCl

  • (CH3)3C-Cl + NaOH

  • (CH3)2CHI + H2O


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