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Hydrocarbons · Question 22

NEET 2018MCQEasy📈 Topic in 12% papers+4−1
1

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

Answer

(4) CH4

Solution

Alkenes and alkynes react with bromine by addition, so (A) must be an alkane.

Wurtz reaction joins two alkyl groups ⇒ the product has twice the carbon atoms of the alkyl bromide.

CH4 Br2, h CH3Br Na, dry ether CH3 - CH3 (2 C atoms, gas)

With CH3-CH3, the Wurtz product would be butane (4 C atoms), not less than four.

∴ (A) is CH4.

Answer: (4)

NEET 2018

Keep practising — Hydrocarbons

2

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
3

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)
4

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)
5

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)
6

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)
7

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

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
8

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)
9

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
10

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
11

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

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