PYQSide ExamsMy practice

Organic Chemistry – Some Basic Principles and Techniques · Question 42

NEET 2013 (Karnataka)MCQMedium📈 Topic in 12% papers+4−1
1

Homolytic fission of the following alkanes forms free radicals CH3-CH3, CH3-CH2-CH3, (CH3)2CH-CH3, CH3-CH2-CH(CH3)2. Increasing order of stability of the radicals is

  1. (CH3)2 C-CH2CH3 < CH3- CH-CH3 < CH3- CH2 < (CH3)3 C
  2. CH3- CH2 < CH3- CH-CH3 < (CH3)2 C-CH2-CH3 < (CH3)3 C
  3. CH3- CH2 < CH3- CH-CH3 < (CH3)3 C < (CH3)2 C-CH2CH3
  4. (CH3)3 C < (CH3)2 C-CH2CH3 < CH3- CH-CH3 < CH3- CH2

Answer

(2) CH3- CH2 < CH3- CH-CH3 < (CH3)2 C-CH2-CH3 < (CH3)3 C

Solution

Stability of alkyl free radicals: 3° > 2° > 1°, due to hyperconjugation (and +I effect of alkyl groups).

CH3- CH2 (1°) < CH3- CH-CH3 (2°) < 3° radicals

Between the 3° radicals: (CH3)3 C has 9 α-hydrogens, (CH3)2 C-CH2-CH3 has 8 α-hydrogens.

⇒ (CH3)3 C is the most stable.

∴ CH3- CH2 < CH3- CH-CH3 < (CH3)2 C-CH2-CH3 < (CH3)3 C

Answer: (2)

NEET 2013 (Karnataka)

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

2

Which of the following chemical system is non aromatic?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2013 (Karnataka)
3

Which nomenclature is not according to IUPAC system?

  1. Br-CH2-CH=CH2 1-Bromoprop-2-ene
  2. [figure] 4-Bromo-2,4-dimethylhexane
  3. [figure] 2-Methyl-3-phenylpentane
  4. [figure] 5-Oxohexanoic acid
AIPMT 2012 (Prelims)
4

Which one of the following is most reactive towards electrophilic reagent?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2011 (Prelims)
5

The correct IUPAC name for the compound is [figure]

  1. 4-ethyl-3-propylhex-1-ene
  2. 3-ethyl-4-ethenylheptane
  3. 3-ethyl-4-propylhex-5-ene
  4. 3-(1-ethylpropyl)hex-1-ene
AIPMT 2011 (Prelims)
6

Which of the following species is not electrophilic in nature?

  1. Cl
  2. BH3
  3. H3 O
  4. NO2
AIPMT 2010 (Mains)
7

The IUPAC name of the compound CH3CH=CHC CH is

  1. pent-4-yn-2-ene
  2. pent-3-en-1-yne
  3. pent-2-en-4-yne
  4. pent-1-yn-3-ene
AIPMT 2010 (Mains)
8

Which one of the following is most reactive towards electrophilic reagent?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2010 (Prelims)
9

The IUPAC name of the compound having the formula CH C-CH=CH2 is

  1. 1-butyne-3-ene
  2. but-1-yne-3-ene
  3. but-1-en-3-yne
  4. 3-butene-1-yne.
AIPMT 2009
10

The state of hybridisation of C2, C3, C5 and C6 of the hydrocarbon, [figure] is in the following sequence

  1. sp3, sp2, sp2 and sp
  2. sp, sp2, sp2 and sp3
  3. sp, sp2, sp3 and sp2
  4. sp, sp3, sp2 and sp3
AIPMT 2009
11

Base strength of [figure] is in the order of

  1. (i) > (iii) > (ii)
  2. (i) > (ii) > (iii)
  3. (ii) > (i) > (iii)
  4. (iii) > (ii) > (i)
AIPMT 2008

All Organic Chemistry – Some Basic Principles and Techniques PYQs →

PDFDownload Organic Chemistry – Some Basic Principles and Techniques PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Chemistry chapters
Physical ChemistrySome Basic Concepts of ChemistryStructure of AtomStates of MatterThermodynamicsEquilibriumRedox ReactionsSolid StateSolutionsElectrochemistryChemical KineticsSurface Chemistry
Inorganic ChemistryClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular StructureHydrogens-Block Elementsp-Block Elements (Group 13 & 14)Environmental ChemistryGeneral Principles of Isolation of Elementsp-Block Elements (Group 15–18)d- and f-Block ElementsCoordination Compounds
Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPolymersChemistry in Everyday LifePrinciples Related to Practical Chemistry