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Alcohols, Phenols and Ethers · Question 35

AIPMT 2011 (Prelims)MCQMedium📈 Topic in 38% papers+4−1
1

In the following reactions, (i) CH3- CH3 |CH- OH |CH-CH3 H+/heat (Major product)A + (Minor product)B (ii) A [in absence of peroxide]HBr, dark (Major product)C + (Minor product)D the major products (A) and (C) are respectively

  1. CH2= CH3 |C-CH2-CH3 and Br |CH2- CH3 |CH-CH2-CH3
  2. CH3- CH3 |C=CH-CH3 and CH3- Br | CH3 |C-CH2-CH3
  3. CH2= CH3 |C-CH2-CH3 and CH3- Br | CH3 |C-CH2-CH3
  4. CH3- CH3 |C=CH-CH3 and CH3- CH3 |CH- Br |CH-CH3

Answer

(2) CH3- CH3 |C=CH-CH3 and CH3- Br | CH3 |C-CH2-CH3

Solution

(i) Acid-catalysed dehydration of 3-methylbutan-2-ol:

Protonation and loss of H2O give the 2° carbocation (CH3)2CH- +CH-CH3.

1,2-Hydride shift gives the more stable 3° carbocation (CH3)2 +C-CH2-CH3.

Loss of H+ gives the more substituted alkene (Saytzeff rule) as the major product:

A = (CH3)2C=CH-CH3 (2-methylbut-2-ene)

(ii) Addition of HBr in the absence of peroxide follows Markovnikov's rule: H goes to the carbon with more H atoms and Br to the more substituted carbon.

C = (CH3)2CBr-CH2-CH3 (2-bromo-2-methylbutane)

Answer: (2)

AIPMT 2011 (Prelims)

Keep practising — Alcohols, Phenols and Ethers

2

When glycerol is treated with excess of HI, it produces

  1. 2-iodopropane
  2. allyl iodide
  3. propene
  4. glycerol triiodide
AIPMT 2010 (Mains)
3

Given are cyclohexanol (I), acetic acid (II), 2, 4, 6-trinitrophenol (III) and phenol (IV). In these the order of decreasing acidic character will be

  1. III > II > IV > I
  2. II > III > I > IV
  3. II > III > IV > I
  4. III > IV > II > I
AIPMT 2010 (Prelims)
4

Among the following four compounds (i) Phenol (ii) Methyl phenol (iii) Meta-nitrophenol (iv) Para-nitrophenol The acidity order is

  1. (iv) > (iii) > (i) > (ii)
  2. (iii) > (iv) > (i) > (ii)
  3. (i) > (iv) > (iii) > (ii)
  4. (ii) > (i) > (iii) > (iv)
AIPMT 2010 (Prelims)
5

Which of the following compounds has the most acidic nature?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2010 (Prelims)
6

Consider the following reaction : Phenol Zn dust X [Anhyd. AlCl3]CH3Cl Y Alkaline KMnO4 Z the product Z is

  1. benzaldehyde
  2. benzoic acid
  3. benzene
  4. toluene
AIPMT 2009
7

HOCH2CH2OH on heating with periodic acid gives

  1. 2HCOOH
  2. [figure]
  3. [figure]
  4. 2CO2
AIPMT 2009
8

Consider the following reaction : Ethanol PBr3 X alc. KOH Y [(ii) H2O, heat](i) H2SO4, room temperature Z the product Z is

  1. CH3CH2-O-CH2-CH3
  2. CH3-CH2-O-SO3H
  3. CH3CH2OH
  4. CH2=CH2
AIPMT 2009
9

In the reaction : CH3- CH3 |CH-CH2-O-CH2-CH3 + HI heated Which of the following compounds will be formed?

  1. CH3- CH3 |CH-CH3 + CH3CH2OH
  2. CH3- CH3 |CH-CH2OH + CH3CH3
  3. CH3- CH3 |CH-CH2OH + CH3CH2I
  4. CH3- CH3 |CH-CH2-I + CH3CH2OH
AIPMT 2007
10

Ethylene oxide when treated with Grignard reagent yields

  1. primary alcohol
  2. secondary alcohol
  3. tertiary alcohol
  4. cyclopropyl alcohol
AIPMT 2006
11

The major organic product in the reaction is CH3-O-CH(CH3)2 + HI products

  1. CH3I + (CH3)2CHOH
  2. CH3OH + (CH3)2CHI
  3. ICH2OCH(CH3)2
  4. CH3O I |C(CH3)2
AIPMT 2006

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