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GS
GS Set-1
Chemistry
Organic Chemistry
115

Organic Chemistry MCQ with Answers

115) HBr reacts with CH₂=CH−OCH₃ under anhydrous conditions at room temperature to give:

CH₃CHO and CH₃Br

BrCH₂CHO and CH₃OH

BrCH₂−CH₂−OCH₃

CH₃−CHBr−OCH₃

Answer is:

CH₃−CHBr−OCH₃

Organic Chemistry MCQ with Answers

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Related Organic Chemistry MCQ with Answers

116) Osmium tetraoxide is used for:

Hydroxylation of alkynes to give trans−isomer

Hydroxylation of alkenes to give cis−isomer

Hydroxylation of alkenes to give syn−addition

Hydroxylation of alkenes to give anti−addition

Answer is:

Hydroxylation of alkenes to give syn−addition

117) Dehydration of cyclopenylcarbinol with conc. H₂SO₄ forms:

Cyclopentene

Cyclohexene

Methyl cyclopentane

None of these

Answer is:

Cyclohexene

118) In water, H−O−H bond angle is 104.5^o, but in ethers (R−O−R), the C−O−C bond angle is about 110^o. The reason to justify it, is:

Positive inductive effect of alkyl groups is more than that of hydrogen

The alkyl group is polar, while hydrogen is not

Distortion caused by the lone pair of oxygen atom is more than compensated by the bulky alkyl groups

The hybridisation of oxygen atoms is different in ethers and in water

Answer is:

Distortion caused by the lone pair of oxygen atom is more than compensated by the bulky alkyl groups

Explanation:

Bulky groups counter balance the repulsion caused by the lone pairs.

119) In the reaction of phenol with CHCl₃ and aqueous NaOH at 70^oC, the electrophile attacking the ring is:

CHCl₃

⋅CHCl₂

:CCl₂

COCl₂

Answer is:

:CCl₂

Organic Chemistry MCQ with Answers

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