MULTIPLE CHOICE QUESTIONS Of chapter benzene of Pharmaceutical organic chemistry, 3rd semester B.Pharmacy
1. Benzene is an
- a) Aliphatic compound
- b) Aromatic compound
- c) Heterocyclic compound
- d) None of above
Answer- b) Aromatic compound
2. The molecular formulae for benzene is
- a) C6H5
- b) C6H4
- c) C6H6
- d) C6H7
Answer- c) C6H6
3. Which of the following statement is true?
- a) Benzene resists oxidation
- b) Benzene easily oxidised by oxisiding agent
- c) Benzene behaves like a saturated compound
- d) Both (a) and (c)
Answer- d) Both (a) and (c)
4. Benzene undergoes
- a) Substitution reaction
- b) Addition reaction
- c) Elimination reaction
- d) None of above
Answer- a) Substitution reaction
5. Find the correct statement
- a) Benzene has six C-C sigma bonds and not six C-H sigma bonds
- b) Benzene has six C-H sigma bonds but not six C-C sigma bonds
- c) Benzene has six C-C sigma bonds and six C-H sigma bonds
- d) Benzene has neither six C-C sigma bonds nor the six C-H sigma bonds
Answer- c) Benzene has six C-C sigma bonds and six C-H sigma bonds
6. Huckel Rule is also known as
- a) (4n+2) π rule
- b) (4n+1) π rule
- c) (4n+2) σ rule
- d) (4n+1) σrule
Answer- a) (4n+2) π rule
7. According to Huckel rule which of the following statement is correct
- a) The molecule or ion must be planar
- b) Molecule have cyclic delocalised electron clouds above and below the plane
- c) The total number of x-electrons in the molecules should be (4n+2)
- d) The electron clouds should encompass all the carbon atoms of the cyclic system
- e) All of the above
Answer- e) All of the above
8. Which of the following compound contains six- electron system?
Answer- (d)
9. Benzene act as
- a) Nucleophile
- b) Electrophile
- c) Both (a) and (b)
- d) None of above
Answer- a) Nucleophile
10. Benzene undergoes
- a) Nucleophillic substitution reactions
- b) Electrophillic substitution reactions.
- c) Nucleophillic addition reactions
- d) Electrophillic addition reactions
Answer- b) Electrophillic substitution reactions.
11. Sulphonation of benzene is carried out in the presence of
- a) Conc. Sulphuric acid
- b) Fuming sulphuring acid
- c) Both (a) and (b)
- d) Conc. Hydrochloric acid
Answer- a) Conc. Sulphuric acid
12. Nitration of benzene is caried out in the presence of
- a) Conc. Sulphuric acid
- b) Conc. Nitric acid
- c) Mixture of conc. H2SO4 and conc. HNO3
- d) Conc. HCL
Answer- c) Mixture of conc. H2SO4 and conc. HNO3
13. An aromatic molecule will
- a) Have 4n π electrons
- b) Have (4n+2)π electrons
- c) Be planar
- d) By cyclic
- e) B,C,& D
Answer- e) B,C,& D
14. Which catalyst is used during halogenation of benzene?
- a) Lewis acid
- b) Lewis base
- c) Platinum
- d) Ni/pt
Answer- a) Lewis acid
15. Arenes are
- a) Volatile
- b) Water soluble
- c) Non-carcinogenic
- d) Mostly gases
Answer- a) Volatile
16. Arenes does not undergo
- a) Dehydrogenation
- b) Copuling reaction
- c) Halogenation
- d) Cycloaddition
Answer- a) Dehydrogenation
17. The following reaction is
C6H6 + R Cl Anhyd.AlCl3 C6H6R COCH3 + H Cl
- a) Friedal craft’s acylation
- b) Friedal crafts alkylation
- c) Nitration
- d) Halogenation
Answer- b) Friedal crafts alkylation
18. Identify the following reaction
C6H6+ CH3COCI Anhyd.AlCl3 C6H5 COCH3 +HCl
- a) Friedal crafts acylation
- b) Friedal crafts alkylation
- c) Halogenation
- d) Sulphonation
Answer- a) Friedal crafts acylation
19. Friedal crafts alkylation is carried out by the reaction between
- a) Benzene and alkyl halide
- b) Benzene and aryl halide
- c) Benzene and other aromatic compounds
- d) Benzene and nitrobenzene
Answer- a) Benzene and alkyl halide
19. Friedal crafts acylation is useful for preparation of
- a) Aromatic aldehydes
- b) Aliphatic aldehydes
- c) Aromatic ketones
- d) Aliphatic ketones
Answer- a) Aromatic aldehydes
21. π bonds in benzene spread over all six carbons, hence they are called
- a) Spectators
- b) Delocalized
- c) Invaders
- d) Inhebitors
Answer- b) Delocalized
22. Organic compounds which contain one or more than one benzene rings are termed as-
- a) Aryls
- b) Acyls
- c) Arenes
- d) Benzenes
Answer- c) Arenes
23. In a benzene molecule, each carbon atom shares one pair of electron to
- a) Neighbouring atom on other side
- b) Neighbouring atom on one side
- c) Hydrogen atom
- d) All of them
Answer- d) All of them
24. Nitration of benzene molecule shows reaction of
- a) Nucleophillic substitution
- b) Electrophillic substitution
- c) Addition reaction
- d) All of above
Answer- b) Electrophillic substitution
25. Number of sigma bonds in a benzene is
- a) 2
- b) 3
- c) 4
- d) 1
Answer- b) 3
26. Simplest arenes is
- a) Alkenes
- b) Phenol
- c) Benzene
- d) Aminarenes
Answer- c) Benzene
27. In many reactions of benzene it maintains its highly stable delocalized pi bonding by
- a) Ions intact
- b) Proton intact
- c) Electrons intact
- d) All of them
Answer- c) Electrons intact
28. With respect to the electrophillic aromatic substitution of benzene which of the following is not true
- a) Benzene acts as electrophile
- b) A proton is lost in final step
- c) Resonance forms are important
- d) A non-aromatic intermediate is formed
Answer- a) Benzene acts as electrophile
29. While considering electrophillic aromatic substitution reactions electron withdrawing substituent (Nitro) are described as:
- a) Ortho/para directing and deactivating
- b) Ortho/para directing and activating
- c) Meta directing and deactivating
- d) Meta directing and activating
Answer- c) Meta directing and deactivating
30. Friedel crafts alkylation works very well with
- a) Tertiary chloride
- b) Acyl chloride
- c) Primary chloride
- d) Without a catalyst
Answer- a) Tertiary chloride
31. When considering electrophillic aromatic substitution reaction the halides are
- a) Ortho/para directing and activating
- b) Ortho/para directing and deactivating
- c) Meta directing and activating
- d) Meta directing and deactivating
Answer- b) Ortho/para directing and deactivating
32. While considering electrophillic aromatic substitution reaction electron donating sub stituents (Methoxy) are
- a) Ortho/para directing and activating
- b) Ortho/para directing and deactivating
- c) Meta directing and activating
- d) Meta directing and deactivating
Answer- a) Ortho/para directing and activating
