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Hydrocarbons · Question 34

AIPMT 2015 (Cancelled)MCQEasy📈 Topic in 62% papers+4−1
1

The reaction of C6H5CH=CHCH3 with HBr produces

  1. C6H5CH2CH2CH2Br
  2. [figure]
  3. C6H5 Br |CHCH2CH3
  4. C6H5CH2 Br |CHCH3

Answer

(3) C6H5 Br |CHCH2CH3

Solution

Addition of HBr is electrophilic and goes through the more stable carbocation.

H adds to the carbon next to CH3 ⇒ C6H5 CH-CH2CH3, a benzylic carbocation stabilised by resonance with the benzene ring (more stable than C6H5CH2 CHCH3).

Br then attacks the benzylic carbon

⇒ product C6H5 Br |CHCH2CH3 (1-bromo-1-phenylpropane)

Answer: (3)

AIPMT 2015 (Cancelled)

Keep practising — Hydrocarbons

2

What products are formed when the following compound is treated with Br2 in the presence of FeBr3? [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2014
3

Some meta-directing substituents in aromatic substitution are given. Which one is most deactivating ?

  1. -COOH
  2. -NO2
  3. -C N
  4. -SO3H
NEET 2013
4

Which of the following compounds will not undergo Friedel-Crafts reaction easily?

  1. Nitrobenzene
  2. Toluene
  3. Cumene
  4. Xylene
NEET 2013
5

Nitrobenzene on reaction with conc. HNO3/H2SO4 at 80-100 C forms which one of the following products?

  1. 1, 4-Dinitrobenzene
  2. 1, 2, 4 - Trinitrobenzene
  3. 1, 2-Dinitrobenzene
  4. 1, 3-Dinitrobenzene
NEET 2013
6

Which of the following reagents will be able to distinguish between 1-butyne and 2-butyne?

  1. NaNH2
  2. HCl
  3. O2
  4. Br2
AIPMT 2012 (Mains)
7

Among the following compounds the one that is most reactive towards electrophilic nitration is

  1. benzoic acid
  2. nitrobenzene
  3. toluene
  4. benzene
AIPMT 2012 (Prelims)
8

Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by

  1. oxidation
  2. cracking
  3. distillation under reduced pressure
  4. hydrolysis
AIPMT 2010 (Prelims)
9

Benzene reacts with CH3Cl in the presence of anhydrous AlCl3 to form

  1. chlorobenzene
  2. benzyl chloride
  3. xylene
  4. toluene.
AIPMT 2009
10

Nitrobenzene can be prepared from benzene by using a mixture of conc. HNO3 and conc. H2SO4. In the mixture, nitric acid acts as a/an

  1. acid
  2. base
  3. catalyst
  4. reducing agent
AIPMT 2009
11

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
AIPMT 2008

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