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Hydrocarbons · Question 12

NEET (UG) 2022MCQEasy📈 Topic in 62% papers+4−1
1

Compound X on reaction with O3 followed by Zn/H2O gives formaldehyde and 2-methyl propanal as products. The compound X is

  1. 3-Methylbut-1-ene
  2. 2-Methylbut-1-ene
  3. 2-Methylbut-2-ene
  4. Pent-2-ene

Answer

(1) 3-Methylbut-1-ene

Solution

Ozonolysis cleaves the C=C bond and converts each doubly bonded carbon into a C=O group.

Products: HCHO (formaldehyde) and (CH3)2CH-CHO (2-methylpropanal)

Joining the two carbonyl carbons by a double bond:

CH2=CH-CH(CH3)-CH3, i.e. 3-methylbut-1-ene

CH2=CH-CH(CH3)2 [(ii) Zn/H2O](i) O3 HCHO + (CH3)2CH-CHO

Answer: (1)

NEET (UG) 2022

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2

The decreasing order of boiling points of the following alkanes is : Choose the correct answer from the options given below :

  1. A > E > C > B > D
  2. A > C > E > D > B
  3. C > D > A > E > B
  4. A > E > B > C > D
NEET (UG) 2022 (Phase 2)
3

The incorrect method for the synthesis of alkenes is

  1. Treating vicinal dihalides with Zn metal
  2. Treating of alkynes with Na in liquid NH3
  3. Heating alkyl halides with alcoholic KOH
  4. Treating alkyl halides in aqueous KOH solution
NEET (UG) 2022 (Phase 2)
4

The major product of the following chemical reaction is : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2021
5

CH3CH2COO-Na+ [Heat]NaOH, +? CH3CH3 + Na2CO3 Consider the above reaction and identify the missing reagent/chemical.

  1. DIBAL-H
  2. B2H6
  3. Red Phosphorus
  4. CaO
NEET (UG) 2021
6

Which of the following alkane cannot be made in good yield by Wurtz reaction?

  1. 2, 3-Dimethylbutane
  2. n-Heptane
  3. n-Butane
  4. n-Hexane
NEET (UG) 2020
7

An alkene on ozonolysis gives methanal as one of the products, Its structure is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2020
8

Among the following, the reaction that proceeds through an electrophilic substitution, is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2019
9

The most suitable reagent for the following conversion, is : [figure]

  1. Zn / HCl
  2. Hg2+/H+, H2O
  3. Na / liquid NH3
  4. H2, Pd/C, quinoline
NEET (UG) 2019
10

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
NEET (UG) 2019
11

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

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