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Hydrocarbons · Question 21

NEET (UG) 2019MCQMedium📈 Topic in 62% papers+4−1
1

An alkene “A” on reaction with O3 and Zn + H2O gives propanone and ethanal in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is :

  1. H3C-CH2- Cl | CH3 |C-CH3
  2. H3C- Cl |CH- CH3 | CH3 |CH
  3. Cl-CH2-CH2- CH3 | CH3 |CH
  4. H3C-CH2- CH2Cl |CH-CH3

Answer

(1) H3C-CH2- Cl | CH3 |C-CH3

Solution

Ozonolysis products: propanone (CH3)2C=O + ethanal O=CH-CH3

⇒ Joining the carbonyl carbons by a double bond: A = 2-methylbut-2-ene, H3C- CH3 |C=CH-CH3

As per Markovnikov's rule, H+ adds to the =CH– carbon to give the more stable 3° carbocation, and Cl- then adds to it:

B = 2-chloro-2-methylbutane, H3C-CH2- Cl | CH3 |C-CH3

Answer: (1)

NEET (UG) 2019

Keep practising — Hydrocarbons

2

Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. (A) is

  1. CH CH
  2. CH2 = CH2
  3. CH3 - CH3
  4. CH4
NEET 2018
3

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
NEET 2017
4

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)
5

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)
6

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)
7

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)
8

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

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
9

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)
10

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
11

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

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