Assertion : Esters which contain α-hydrogens undergo Claise

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 Multiple Choice QuestionsMultiple Choice Questions

831.

When phenol reacts with phthalic anhydride in presence of H2SO4 and heated and hot reaction mixture is poured in NaOH solution, then product formed is

  • alizarin

  • methyl orange

  • fluorescein

  • phenolphthalein.


832.

Dehydration of glycerol produces :

  • propanone

  • allyl alcohol

  • glycol

  • acrolein


833.

In solvents like DMSO, acetonitrile, F- ion of dissolved NaF is more reactive than in methyl alcohol becasue

  • CH3OH is more polar than DMSO and CH3CN

  • CH3OH is less polar than DMSO and CH3CN

  • unsolvated F- ion is DMSO or CH3CN acts more efficiently as nucleophile

  • -OH group is a better leaving group than F- ion


834.

In Oppenauer's oxidation,

  • secondary alcohol is oxidised to carboxylic acid in acetone solvent using aluminium tertiary butoxide

  • secondary alcohol is oxidised to carboxylic acid without affecting the C=C or C=C bond by aluminium tertiary butoxide in acetone solvent

  • secondary alcohol is oxidised to ketone without affecting C=C or C=C bond by aluminium tertiary butoxide

  • secondary alcohol is oxidised to ketone by chromic acid - pyridine complex.


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835.

Assertion : In fused state, calcium chloride cannot be used to dry alcohol or NH3.

Reason : CaCl2 is not a good dessicant.

  • 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.


836.

 Soda lime A ? Anisole

Reagent in second step should be :

  • CH3Cl

  • KOH + C2H5OH

  • KOH + C2H5SH

  • KOH + Cl2


837.

Assertion : Ethers can be dried by using sodium wire.

Reason : Ethers do not react with sodium.

  • 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


838.

Assertion: C2H5Br reacts with alcoholic solution of AgNO2 to form nitroethane as the major product.

Reason : NO2- is an ambidient ion.

  • 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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839.

Assertion : Esters which contain α-hydrogens undergo Claisen condensation.

Reason : LiAlH4 reduction of esters gives acids.

  • 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


C.

If assertion is true but reason is false

Esters with α- hydrogen form carbanion when treated with base. It brings about nucleophilic substitution at the carbonyl group of the other molecule of the ester to yield β-keto ester. LiAlH4 reduces esters to alcohols.


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840.

CH3OC2H5 and (CH3)3C-OCH3 are treated with hydroiodic acid. The fragments after reactions obtained are

  • CH3I + HOC2H5; (CH3)3C-I + HOCH3

  • CH3OH + C2H5I; (CH3)3Cl + HOCH3

  • CH3OH + C2H5; (CH3)3C-OH + CH3I

  • CH3I + HOC2H5; CH3I + (CH3)3C-OH


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