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Hydrocarbons · Question 35

AIPMT 2014MCQMedium📈 Topic in 12% papers+4−1
1

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]

Answer

(3) [figure]

Solution

As per NCERT, -CH3 is an activating, ortho- and para-directing group in electrophilic substitution.

In 1,3-dimethylbenzene, C-4 and C-6 are each ortho to one -CH3 and para to the other ⇒ most activated positions.

C-2 is also activated but lies between the two -CH3 groups ⇒ sterically hindered; C-5 is meta to both groups.

∴ Br enters at C-4 / C-6 (equivalent positions), as shown in option (3):

[figure]

Answer: (3)

AIPMT 2014

Keep practising — Hydrocarbons

2

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
3

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

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

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
5

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)
6

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)
7

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)
8

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

  1. chlorobenzene
  2. benzyl chloride
  3. xylene
  4. toluene.
AIPMT 2009
9

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
10

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
11

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

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