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Hydrocarbons · Question 23

NEET 2017MCQEasy📈 Topic in 12% papers+4−1
1

Predict the correct intermediate and product in the following reaction : H3C-C CH [HgSO4]H2O, H2SO4 (A)Intermediate (B)Product

  1. A : H3C- OH |C=CH2 B : H3C- SO4 |C=CH2
  2. A : H3C- O \|C-CH3 B : H3C-C CH
  3. A : H3C- OH |C=CH2 B : H3C- O \|C-CH3
  4. A : H3C- SO4 |C=CH2 B : H3C- O \|C-CH3

Answer

(3) A : H3C- OH |C=CH2 B : H3C- O \|C-CH3

Solution

As per NCERT, alkynes add water in the presence of HgSO4 and dilute H2SO4 at 333 K to give carbonyl compounds.

Markovnikov addition of H+ and OH- to propyne gives the enol (A):

H3C-C CH [HgSO4]H2O, H2SO4 H3C- OH |C=CH2

The enol is unstable and tautomerises to the ketone (B), propanone:

H3C- OH |C=CH2 H3C- O \|C-CH3

Answer: (3)

NEET 2017

Keep practising — Hydrocarbons

2

Consider the nitration of benzene using mixed conc. H2SO4 and HNO3. If a large amount of KHSO4 is added to the mixture, the rate of nitration will be

  1. unchanged
  2. doubled
  3. faster
  4. slower
NEET 2016 (Phase 1)
3

In the reaction H-C CH [(ii) CH3CH2Br](i) NaNH2/liq. NH3 X [(ii) CH3CH2Br](i) NaNH2/liq. NH3 Y, X and Y are

  1. X = 2-Butyne, Y = 2-Hexyne
  2. X = 1-Butyne, Y = 2-Hexyne
  3. X = 1-Butyne, Y = 3-Hexyne
  4. X = 2-Butyne, Y = 3-Hexyne
NEET 2016 (Phase 1)
4

Which of the following can be used as halide component for Friedel-Crafts reaction?

  1. Chlorobenzene
  2. Bromobenzene
  3. Chloroethene
  4. Isopropyl chloride
NEET 2016 (Phase 2)
5

Which of the following compounds shall not produce propene by reaction with HBr followed by elimination or direct only elimination reaction ?

  1. [figure]
  2. H3C- H2 |C-CH2OH
  3. H2C=C=O
  4. H3C- H2 |C-CH2Br
NEET 2016 (Phase 2)
6

In the given reaction, [figure] the product P is

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
7

The compound that will react most readily with gaseous bromine has the formula

  1. C3H6
  2. C2H2
  3. C4H10
  4. C2H4
NEET 2016 (Phase 2)
8

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]
AIPMT 2015
9

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
10

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
11

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)

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