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Hydrocarbons · Question 44

AIPMT 2008MCQMedium📈 Topic in 62% papers+4−1
1

H3C- CH3 |CH-CH=CH2 + HBr A A (predominantly) is

  1. CH3- Br |CH- CH3 |CH-CH3
  2. CH3- CH3 |CH- Br |CH-CH3
  3. CH3- CH3 |CH-CH2-CH2Br
  4. CH3- Br | CH3 |C-CH2CH3

Answer

(4) CH3- Br | CH3 |C-CH2CH3

Solution

Addition of HBr follows Markovnikov's rule through a carbocation intermediate.

Step 1: H+ adds to the terminal CH2 and gives a 2° carbocation:

CH3- CH3 |CH- CH-CH3

Step 2: a 1,2-hydride shift from the neighbouring carbon gives the more stable 3° carbocation:

CH3- CH3 | C-CH2-CH3

Step 3: Br- attacks the 3° carbocation:

CH3- Br | CH3 |C-CH2CH3 (2-bromo-2-methylbutane)

A (predominantly) is 2-bromo-2-methylbutane.

Answer: (4)

AIPMT 2008

Keep practising — Hydrocarbons

2

The order of decreasing reactivity towards an electrophilic reagent, for the following would be (i) benzene (ii) toluene (iii) chlorobenzene (iv) phenol

  1. (ii) > (iv) > (i) > (iii)
  2. (iv) > (iii) > (ii) > (i)
  3. (iv) > (ii) > (i) > (iii)
  4. (i) > (ii) > (iii) > (iv)
AIPMT 2007
3

Predict the product C obtained in the following reaction of 1-butyne. CH3CH2-C CH + HCl B HI C

  1. CH3-CH2-CH2- Cl | I |C-H
  2. CH3-CH2- I |CH-CH2Cl
  3. CH3CH2- Cl | I |C-CH3
  4. CH3- Cl |CH-CH2CH2I
AIPMT 2007
4

Which of the compound with molecular formula C5H10 yields acetone on ozonolysis?

  1. 3-Methyl-1-butene
  2. Cyclopentane
  3. 2-Methyl-1-butene
  4. 2-Methyl-2-butene
AIPMT 2007
5

The correct order regarding the electronegativity of hybrid orbitals of carbon is

  1. sp < sp2 < sp3
  2. sp > sp2 < sp3
  3. sp > sp2 > sp3
  4. sp < sp2 > sp3
AIPMT 2006
6

Which one of the following alkenes will react faster with H2 under catalytic hydrogenation conditions ?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2005
7

Products of the following reaction : CH3C CCH2CH3 [(ii) hydrolysis](i) O3 are

  1. CH3COOH + CO2
  2. CH3COOH + HOOC.CH2CH3
  3. CH3CHO + CH3CH2CHO
  4. CH3COOH + CH3COCH3
AIPMT 2005
8

Using anhydrous AlCl3 as catalyst, which one of the following reactions produces ethylbenzene (PhEt)?

  1. H3C-CH2OH + C6H6
  2. CH3-CH=CH2 + C6H6
  3. H2C=CH2 + C6H6
  4. H3C-CH3 + C6H6
AIPMT 2004
9

Reaction of HBr with propene in the presence of peroxide gives

  1. isopropyl bromide
  2. 3-bromopropane
  3. allyl bromide
  4. n-propyl bromide
AIPMT 2004
10

The compound CH3- CH3 |C=CH-CH3 on reaction with NaIO4 in the presence of KMnO4 gives

  1. CH3COCH3
  2. CH3COCH3 + CH3COOH
  3. CH3COCH3 + CH3CHO
  4. CH3CHO + CO2
AIPMT 2003
11

The correct order of reactivity towards the electrophilic substitution of the compounds aniline (I), benzene (II) and nitrobenzene (III) is

  1. III > II > I
  2. II > III > I
  3. I < II > III
  4. I > II > III
AIPMT 2003

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