PYQSide ExamsMy practice

Organic Chemistry – Some Basic Principles and Techniques · Question 22

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

The IUPAC name of the compound [figure]

  1. 5-formylhex-2-en-3-one
  2. 5-methyl-4-oxohex-2-en-5-al
  3. 3-keto-2-methylhex-5-enal
  4. 3-keto-2-methylhex-4-enal

Answer

(4) 3-keto-2-methylhex-4-enal

Solution

Principal functional group: –CHO ⇒ suffix '-al'; its carbon is C-1.

Longest chain containing –CHO and the C=C has 6 carbons:

1CHO- 2CH(CH3)- 3CO- 4CH= 5CH- 6CH3

Substituents: methyl at C-2, keto (oxo) group at C-3; double bond between C-4 and C-5 ⇒ hex-4-enal.

∴ Name: 3-keto-2-methylhex-4-enal (keto = oxo; in current IUPAC style written 2-methyl-3-oxohex-4-enal).

Answer: (4)

NEET 2017

Keep practising — Organic Chemistry – Some Basic Principles and Techniques

2

Which one is the correct order of acidity?

  1. CH CH > CH3-C CH > CH2=CH2 > CH3-CH3
  2. CH CH > CH2=CH2 > CH3-C CH > CH3-CH3
  3. CH3-CH3 > CH2=CH2 > CH3-C CH > CH CH
  4. CH2=CH2 > CH3-CH=CH2 > CH3-C CH > CH CH
NEET 2017
3

For the following reactions : (A) CH3CH2CH2Br + KOH CH3CH=CH2 + KBr + H2O (B) [figure] (C) [figure] Which of the following statements is correct?

  1. (A) is elimination, (B) and (C) are substitution reactions.
  2. (A) is substitution, (B) and (C) are addition reactions.
  3. (A) and (B) are elimination reactions and (C) is addition reaction.
  4. (A) is elimination, (B) is substitution and (C) is addition reaction.
NEET 2016 (Phase 1)
4

The pair of electrons in the given carbanion, CH3C C-, is present in which of the following orbitals?

  1. sp2
  2. sp
  3. 2p
  4. sp3
NEET 2016 (Phase 1)
5

In which of the following molecules, atoms are coplanar?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
6

In pyrrole the electron density is maximum on [figure]

  1. 2 and 3
  2. 3 and 4
  3. 2 and 4
  4. 2 and 5
NEET 2016 (Phase 2)
7

Which of the following statements is not correct for a nucleophile?

  1. Ammonia is a nucleophile.
  2. Nucleophiles attack low e- density sites.
  3. Nucleophiles are not electron seeking.
  4. Nucleophile is a Lewis acid.
AIPMT 2015
8

The total number of π-bond electrons in the following structure is [figure]

  1. 12
  2. 16
  3. 4
  4. 8
AIPMT 2015 (Cancelled)
9

Which of the following is the most correct electron displacement for a nucleophilic reaction to take place?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2015 (Cancelled)
10

Consider the following compounds : [figure] Hyperconjugation occurs in

  1. III only
  2. I and III
  3. I only
  4. II only
AIPMT 2015 (Cancelled)
11

The enolic form of ethyl acetoacetate as shown below has [figure]

  1. 9 sigma bonds and 2 pi-bonds
  2. 9 sigma bonds and 1 pi-bond
  3. 18 sigma bonds and 2 pi-bonds
  4. 16 sigma bonds and 1 pi-bond.
AIPMT 2015 (Cancelled)

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