Some Basic Concepts of Organic Chemistry

Some Basic Concepts of Organic Chemistry

Que 1. Select the molecule which has only one л – bond
(a) CH2 = CH2
(b) CH2 = CHCHO
(c) CH3CH = CH2

Que 2. 2-Pentene contains
(a) 15 σ – and one л – bond
(b) 14 σ -and one л – bond
(c) 15 σ – and two л – bonds
(d) 14 σ – and two л – bonds

Que 3. Which of the following does not represent the 2 – Bromo pentane?

(a) (ii) and (iii)
(b) Only (ii)
(c) (ii) and (iii)
(d) (iii) and (v)

Que 4. Which of the following is incorrectly matched –
(a) Vinegar → Carboxylic acid
(b) C2H6 → Alkane
(c) Ethanol → Alcohol
(d) Methanol → Ketone

Que 5. The functional group present in organic, acid is 
(a) – OH
(b) – CHO
(c) –COOH
(d) > C = O

Some Basic Concepts of Organic Chemistry

Que 6. Which of these contains the carbonyl group?
(a) Ketones
(b) Aldehydes
(c) Esters
(d) All of these

Que 7. The number of secondary hydrogens in 2, 2-dimethylbutane is
(a) 8
(b) 6
(c) 4
(d) 2

Que 8. The compound which has one isopropyl group is
(a) 2, 2, 3, 3 – Tetramethylpentane
(b) 2, 2 – Dimethylpentane
(c) 2, 2, 3- Trimethylpentane
(d) 2- Methypentane

Que 9. What is the IUPAC name of t-butyl alcohol?
(a) Butanol–2
(b) 2–Methyl-propan–2-ol
(c) Butanol–1
(d) Propanol-2

Que 10. The IUPAC name of CH3COCH (CH3)2 is –
(a) Isopropyl methyl ketone
(b) 2-methyl-3-butanone
(c) 4-methylisopropyl ketone
(d) 3-methyl-2-butanone

Que 11. What is the IUPAC name of the following compound?

(a) 2-methyl-4-hexanamine
(b) 5-methyl-3-hexanamine
(c) 2-methyl-4-amino hexane
(d) 5-methyl-3-amino hexane

Que 12. Identify the correct IUPAC name of the compound given below

(a) 4 – benzyl – 5 – methyl hexanal
(b) 2 – methyl – 3 – phenyl hexanal
(c) 5 – isopropyl – 5 – phenyl butanal
(d) 5 – methyl – 4 – phenyl hexanal

Que 13. Which of the following is a 3-methylbutyl group?
(b) (CH3CH2)2CH –
(c) (CH3)3CCH2
(d) (CH3)2CHCH2CH2

Que 14. CH3CH2OH and CH3OCH3 are the examples of
(a) Chain isomerism
(b) Functional isomerism
(c) Position isomerism
(d) Metamerism

Que 15. The IUPAC name of the compound CH3 — CH(CH3) — CO – CH3, is
(a) 3-methyl 2-butanone
(b) 2-methyl 3-butanone
(c) isopropyl methyl ketone
(d) methyl isopropyl ketone

Some Basic Concepts of Organic Chemistry

Que 16. Methoxyethane and propanol are examples of isomerism of the type
(a) Structural
(b) Position
(c) Functional
(d) Tautomerism

Que 17. Which of the following ions is most stable?

Que 18. Select the most stable carbocation amongst the following

Que 19. Heterolytic fission of C – Br bond results in the formation of
(a) free radical                          (b) carbanion
(c) carbocation                         (d) Both (b) and (c)

Que 20. What is the correct order of decreasing stability of the following cations?

(a) II > I > III
(b) II > III > I
(c) III > I > II
(d) I > II > III

Que 21. The shape of methyl carbanion is similar to that of –
(a) BF3
(b) NH3
(c) Methyl free radical
(d)Methyl carbocation

Que 22. Which of the following is the strongest nucleophile
(a) Br
(b) :OH
(c) :CN
(d) C2H5O:

Que 23. Which of the following is an electrophile?
(a) Lewis acid
(b) Lewis base
(c) Negatively charged species
(d) None of the above

Que 24. Which of the following pairs represent electrophiles?
(a) AlCl3, H2O
(b) SO3, NO2+
(c) BF3, H2O
(d) NH3, SO3

Que 25. The increasing order of stability of the following free radicals is

Some Basic Concepts of Organic Chemistry

Que 26. Point out the incorrect statement about resonance?
(a) Resonance structures should have equal energy
(b) In resonating structures, the constituent atoms must be in the same position
(c) In resonating structures, there should not be the same number of electron pairs
(d) Resonating structures should differ only in the location of electrons around the constituent atoms

Que 27. Which of the following is an example of an elimination reaction?
(a) Chlorination of methane
(b) Dehydration of ethanol
(c) Nitration of benzene
(d) Hydroxylation of ethylene

Que 28. Which of the following is not correctly matched?
 Group showing + R effect                   Group showing – R effect
(a) – NHCOR                                       – COOH
(b) = C = O                                           – OH
(c) – OR                                               – CHO
(d) – OCOR                                          – NO2

Que 29. The electromeric effect is a
(a) Permanent effect
(b) Temporary effect
(c) Resonance effect
(d) Inductive effect

Que 30. The kind of delocalization involving sigma bond orbitals is called
(a) Inductive effect
(b) Hyperconjugation effect
(c) Electromeric effect
(d) Mesomeric effect

Que 31. Hyperconjugation is most useful for stabilizing which of the following carbocations?
(a) neo-Pentyl
(b) tert-Butyl
(c) iso-Propyl
(d) Ethyl

Que 32. Which out of A, B, C, and D is/are not correctly categorized.

Nucleophile Electrophile
A HS Cl+
B BF3 (CH3)3 N
C H2N -C=O
X – Halogen

(a) B, C and D
(b) C and D
(c) C only
(d) B and D

Que 33. The IUPAC name of the following compound is
(CH3)2CH – CH2CH = CH – CH = CH – CH (CH3)C2H5
(a) 1,1,7,7-tetramethyl-2,5-octadiene
(b) 2,8-dimethyl-3,6-decadiene
(c) 1,5-di-iso-propyl-1,4-hexadiene
(d) 2,8-dimethyl-4,6-decadiene

Que 34. The least number of carbon atoms in alkane showing isomerism is
(a) 3
(b) 1
(c) 2
(d) 4

Que 35. The organic reaction which proceeds through heterolytic bond cleavage is called ________
(a) Ionic
(b) Polar
(c) Nonpolar
(d) Both (a) and (b)

Some Basic Concepts of Organic Chemistry

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