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Hydrocarbons · Question 30

AIPMT 2015MCQMedium📈 Topic in 62% papers+4−1
1

In the reaction with HCl, an alkene reacts in accordance with the Markovnikov's rule to give a product 1-chloro-1-methylcyclohexane. The possible alkene is

  1. [figure] (A)
  2. [figure] (B)
  3. (A) and (B)
  4. [figure]

Answer

(3) (A) and (B)

Solution

As per NCERT, in the addition of HX to an unsymmetrical alkene (Markovnikov's rule), the negative part (Cl-) goes to the double-bond carbon carrying fewer hydrogen atoms, through the more stable carbocation.

(A) Methylenecyclohexane: H+ adds to =CH2 ⇒ 3° carbocation at the ring carbon ⇒ Cl- attacks it:

[figure]

(B) 1-Methylcyclohexene: H+ adds to C-2 ⇒ 3° carbocation at C-1 (bearing CH3) ⇒ the same product:

[figure]

(D) 3-Methylcyclohexene gives a 2° carbocation not at the carbon bearing CH3 ⇒ 1-chloro-2-methyl- / 1-chloro-3-methylcyclohexane, not 1-chloro-1-methylcyclohexane.

∴ Both (A) and (B) give 1-chloro-1-methylcyclohexane.

Answer: (3)

AIPMT 2015

Keep practising — Hydrocarbons

2

2,3-Dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid?

  1. (CH3)3CCH=CH2
  2. (CH3)2C=CHCH2CH3
  3. (CH3)2CHCH2CH=CH2
  4. (CH3)2CH- CH3 |CH-CH=CH2
AIPMT 2015
3

The oxidation of benzene by V2O5 in the presence of air produces

  1. maleic anhydride
  2. benzoic acid
  3. benzaldehyde
  4. benzoic anhydride.
AIPMT 2015
4

A single compound of the structure, [figure] is obtainable from ozonolysis of which of the following cyclic compounds?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2015 (Cancelled)
5

The reaction of C6H5CH=CHCH3 with HBr produces

  1. C6H5CH2CH2CH2Br
  2. [figure]
  3. C6H5 Br |CHCH2CH3
  4. C6H5CH2 Br |CHCH3
AIPMT 2015 (Cancelled)
6

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
7

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
8

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

  1. Nitrobenzene
  2. Toluene
  3. Cumene
  4. Xylene
NEET 2013
9

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
10

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)
11

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)

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