Assertion : Aldol condensation can be catalysed both by acids and

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 Multiple Choice QuestionsMultiple Choice Questions

1021.

Methyl isocyanide on hydrolysis gives :

  • CH3NH2

  • HCOOH

  • CH3COOH

  • Both (a) and (b)


1022.

Cyclohexene on ozonolysis followed by reaction with zinc dust and water gives compound E. Compound Eon further treatment with aqueous KOH yields compound F. Compound F is


1023.

Maximum decarboxylation occurs in

  • CH3COOH

  • C6H5COOH

  • C6H5CH2COOH

  • CH3COCH2COOH


1024.

The correct increasing order of reactivity for the following molecules towards electrophilic aromatic substitution is

  • I < IV < II < III

  • I < IV < II < IV

  • I < III < II < IV

  • I < III < IV < II


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1025.

The corrcet decreasing order of pKb is 

  • I > II > III > IV

  • III > IV > II > I

  • II > III > IV > I

  • IV > II > I > III


1026.

The correct decreasing order of pKa is

  • II > IV > I > III

  • IV > II > III > I

  • III > II > IV > I

  • IV > I > II > III


1027.

The reagent used in Clemmensen's reduction is :

  • conc H2SO4

  • Zn-Hg / conc HCl

  • aq KOH

  • alc KOH


1028.

The product formed when hydroxylamine condenses with a carbonyl compound is called :

  • hydrazide

  • oxime

  • hydrazine

  • hydrazone


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1029.

Asssertion: CH3-C(COOC2H5)=CH-COOH is 3-carbethoxy-2-butenoic acid.

Reason : Principal functional group gets lowest number followed by double bond or triple bond.

  • 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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1030.

Assertion : Aldol condensation can be catalysed both by acids and bases.

Reason : β-Hydroxy aldehydes or ketones readily undergo acid catalysed dehydration.

  • 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.


B.

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

Both carbanions (formed in presence of base) and enol form (formed in presence of an acid) act as nucleophiles and hence add on the carbonyl group of aldehydes and ketones to give aldols.


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