AROMATIC HYDROCARBONS LEVEL I AROMATIC HYDROCARBONS AROMATIC HYDROCARBONS

AROMATIC HYDROCARBONS LEVEL - I AROMATIC HYDROCARBONS

AROMATIC HYDROCARBONS LEVEL - I OBJECTIVE QUESTIONS LEVEL-I

AROMATIC HYDROCARBONS LEVEL - I 1) Benzene was first isolated by …. 1) Mitscherlich 2) Faraday 3) Kekule 4) Berzelius LEVEL - I

AROMATIC HYDROCARBONS 2) The name, benzene was proposed by …. 1) Mitscherlich 2) Faraday 3) Kekule 4) Dewar LEVEL - I

AROMATIC HYDROCARBONS 3) Structure of benzene was proposed by… 1) Mitscherlich 2) Faraday 3) Kekule 4) Berzelius LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 4) Compared with aliphatic hydrocarbons, the number of hydrogens in aromatic hydrocarbons is… 1) less 2) more 3) equal 4) either 1 or 2 Solution : C 6 H 6 ( Aromatic) C 6 H 14 ( Aliphatic) Number of hydrogens are less in armoatic compounds

AROMATIC HYDROCARBONS LEVEL - I 5) The C – C bond lengths in benzene are… 1) 1. 54 A 0 & 1. 34 A 0 2) 1. 34 A 0 & 1. 20 A 0 3) 1. 39 A 0 only 4) 1. 20 A 0 only Solution : Due to resonance, bond lengths in benzene lie in between 1. 34 A 0 i. e. , 1. 39 A 0

AROMATIC HYDROCARBONS LEVEL - I 6) The carbon-carbon bonds in benzene are … 1) sp 3 – sp 2 2) sp 2 – sp 2 Solution : All the carbons in benzene are SP 2 hybridized.

AROMATIC HYDROCARBONS 7) The six carbon atoms of Benzene are of …. 1) One type 2) Two types 3) Three types 4) Four types LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 8) (4 n + 2) π electrons represent the following rule… 1) Kekule 2) Huckel’s 3) Craig 4) Saytzeff’s

AROMATIC HYDROCARBONS 9) Shape of the benzene is… 1) tetrahedral 2) trigonal planar 3) hexagonal planar 4) linear LEVEL - I

AROMATIC HYDROCARBONS 10) Hybridization of each carbon in the benzene… 1) sp 3 2) sp 3) sp 2 4) sp and sp 2 LEVEL - I

AROMATIC HYDROCARBONS 11) The general formula of benzene is… 1) Cn. H 2 n+6 2) Cn. H 2 n-6 3) Cn. H 2 n-4 4) Cn. H 2 n-2 LEVEL - I

AROMATIC HYDROCARBONS 12)The resonance energy of the benzene is… 1) 36 k. J 2) 85. 8 k. J 3) 150. 48 k. J 4) 64 k. J Solution : 36 K. cal = 150. 48 k. J LEVEL - I

AROMATIC HYDROCARBONS 1) 2 2) 6 3) 4 4) 14 Solution : 3�� bonds i. e. , 6�� electrons LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I PREPARATION 14) Formation of Benzene from Acetylene …. . 1) Trimerisation 2) Tetramerisation 3) Dimerisation 4) Condensation Solution : 3 molecules of Acetylene are involved in the reaction

AROMATIC HYDROCARBONS LEVEL - I 15) Preparation of benzene from phenol is… 1) reduction 2) oxidation 3) addition 4) dehydrogenation Solution : C 6 H 5 OH Zn C 6 H 6 + Zn. O [removal of oxygen]

AROMATIC HYDROCARBONS LEVEL - I 16) Sodium benzoate gives benzene in presence of …. 1) Na. OH + Ca. O Solution : Na. OH + Ca. O

AROMATIC HYDROCARBONS LEVEL - I 17) Benzene is obtained from benzene sulphonic acid by… 1) hydration 2) hydrolysis 3) condensation 4) polymerisation Solution : Suoer heated steam (or) acid

AROMATIC HYDROCARBONS LEVEL - I 18) Benzene sulphonic acid is hydrolyzed with 1) Acid 2) Base 3) Superheated steam 4) Both (1)& (3) Solution : Super heated steam (or) acid to get benzene…

AROMATIC HYDROCARBONS LEVEL - I 19) Benzoic acid gives Benzene on being heated with X. Phenol gives benzene on being heated with Y. Therefore X and Y are respectively…. 1) Soda lime and copper 2) Zinc dust and Na. OH 3) Zinc dust and Soda lime 4) Soda lime and Zinc dust Solution : Na. OH + Ca. O mhgg Zn dust

AROMATIC HYDROCARBONS LEVEL - I 20) Destructive distillation of coal, means… 1) heating to low temperature in absence of air 2) heating to high temperature in presence of air 3) heating to low temperature in presence of air 4) heating to high temperature in absence of air

AROMATIC HYDROCARBONS LEVEL - I 21) When coal is subjected to destructive distillation, the important products obtained are. . 1) Light oil, Middle oil, Heavy oil, Anthracene oil 2) Coal gas, Coaltar, Ammonical liquor and pitch 3) Benzene , Toluene, Xylene, Naphthalene 4) All the above

AROMATIC HYDROCARBONS 22) Coal tar is obtained as a byproduct during… 1) destructive distillation of wood 2) destructive distillation of coal 3) destructive distillation of bones 4) all the above LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 23) Coal tar is …. 1) Yellow, light liquid with pleasant odour 2) Yellow, light liquid with unpleasant odour 3) Black viscous oily liquid with unpleasant odour 4) Black viscous oily liquid with pleasant odour

AROMATIC HYDROCARBONS LEVEL - I 24) Light oil fraction can be obtained from the following fractional distillation… 1) coal 2) coke 3) coal tar 4) coal gas

AROMATIC HYDROCARBONS LEVEL - I 25) Benzene can be obtained from the following fraction… 1) light oil fraction 2) middle oil fraction 3) heavy oil fraction 4) anthracene oil fraction

AROMATIC HYDROCARBONS 26) Light oil is the boiling fraction collected at… 1) 1100 C 2) 2700 C 3) 4000 C 4)1700 C LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 27) The aromatic compounds present in the middle oil fraction are … 1) Benzene, Naphthalene, Anthracene 2) Naphthalene, pyridine, phenol 3) Naphthalene , Pyridine 4) Toluene, Cresol

AROMATIC HYDROCARBONS LEVEL - I 28) The aromatic compounds present in the heavy oil fraction are… 1) benzene, naphthalene, anthracene 2) naphthalene, pryidine, phenol 3) naphthalene, pyridine 4) cresols

AROMATIC HYDROCARBONS LEVEL - I 29) In the distillation of green oil, the aromatic compounds present are. . 1) Anthracene, Phenanthrene 2) Naphthalene, Pyridine, Phenol 3) Naphthalene, Pyridine 4) Toluene, Cresol

AROMATIC HYDROCARBONS LEVEL - I 30) The basic impurities present in light oil are removed by washing with … 1) Nitric acid 2) Hydrochloric acid 3) Sulphuric acid 4) Potassium hydroxide

AROMATIC HYDROCARBONS LEVEL - I 31) The solid residue left behind in iron retorts during the fractional distillation of coal tar is …. 1) Benzene 2) Ammonical liquor 3) Pearlash 4) Pitch

AROMATIC HYDROCARBONS LEVEL - I 32) To remove phenol, present in light oil, it is treated by washing with… 1) Na. OH 2) HCl 3) H 2 SO 4 4) KNO 3 Solution : Na. OH

AROMATIC HYDROCARBONS LEVEL - I 33) Fractional distillation of coal tar at 170 -2300 C produces …… 1) Heavy oil 2) Light oil 3) Middle oil 4) Anthracene oil

AROMATIC HYDROCARBONS 34) List-1 Fraction A) Heavy oil B) Anthracene oil C) Light oil LEVEL - I List-2 Temperature 1) Up to 1700 C D) Middle oil The correct answer is A B C D 2) 170 – 2300 C 3) 230 – 2700 C 4) 270 – 4000 C A B C D 1) 5 4 3 1 3) 3 1 4 2 2) 1 2 3 4 4) 3 4 1 2

AROMATIC HYDROCARBONS LEVEL - I PROPERTIES 35) Which of the following is the strongest o, p-directing group ? 1) –OH 3) –OCH 3 Solution : 2) –Cl 4) –CH 3 -NH 2, - NH – R , - NR 2, - OH “O” and “P” directing Strength increases -OH group of strong activating o, p – directing group

AROMATIC HYDROCARBONS 36) Benzene is purified by …. 1) Distillation 2) Fractional distillation 3) Evaporation 4) Sublimation LEVEL - I

AROMATIC HYDROCARBONS 37) The boiling point of benzene is …. 1) 1700 C 2) 800 C 3) 2500 C 4) 2700 C LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 38) Some statements regarding Benzene are given below…. 1) Benzene is an aromatic compound 4) Benzene gives fission products during ozonolysis Here the correct statement is. . 1) A, B, C are correct 2) A, B and D are correct 3) A, B are correct 4) A, C, D are correct

AROMATIC HYDROCARBONS LEVEL - I 39) The two structures of benzene proposed by Kekule differ in … 1) The position of carbon nuclei 2) The position of hydrogen nuclei 3) The position of the single bonds 4) The position of the double bonds

AROMATIC HYDROCARBONS LEVEL - I 40) The function of anhydrous Al. Cl 3 in the Friedal-Crafts reaction is… 1) to absorb water 2) to absorb HCl 3) to produce electrophile 4) to produce nucleophile

AROMATIC HYDROCARBONS Red hot Metal tube LEVEL - I Fuming H 2 SO 4 1) Benzene 2) Benzene sulphonic acid 3) Chlorobenzene 4) Toluene Solution : Red hot metal tube Funnkng H 2 SO 4

AROMATIC HYDROCARBONS 42) C 6 H 6 easily undergoes …… 1) Ring fission reaction since it is unstable 2) Addition reactions since it is saturated 3) Electrophilic substitution reactions 4) Nucleophilic substitution reactions Solution : Red hot metal tube Funnkng H 2 SO 4 LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I 43) Which of the following reactions is useful to convert benzene into toluene? 1) wurtz reaction 2) kolbe’s reaction 3) friedel – craft’s alkylation 4) Grignard reagent Solution : Anhy Al. Cl 3

AROMATIC HYDROCARBONS 44) Ca. C 2 H O B and C are 2 A Red tube hot LEVEL - I B Al. Cl 3 CH 3 Cl C ; In this sequence 1) Benzene & acetylene 2) Toluene & Benzene 3) Benzene & Toluene 4) Toluene & Acetylene Solution : Red hot metal tube Anhy. Al. Cl 3

AROMATIC HYDROCARBONS LEVEL - I 45) Which of the following is the most reactive towards ring nitration? 1) benzene 2) mesitylene 3) toluene 4) m - Xylene CH 3 Solution : C 6 H 3(CH 3)3 contains “ 3” Electron releasing groups H 3 C Mesitylene CH 3

AROMATIC HYDROCARBONS LEVEL - I 46) Which of the following will have a fastest rate of reaction with Br 2 /Fe. Br 3? 1) 2) 3) 4) Solution : +M effect of methoxy group

AROMATIC HYDROCARBONS LEVEL - I 47) Among the following compounds (I - III), the correct order in reaction with electrophile is …. III) I) 1) II > I 2) III < II 3) I > III 4) I = II > III Solution : +M effect of methoxy group

AROMATIC HYDROCARBONS LEVEL - I 48) In Friedal–Crafts alkylation, besides Al. Cl 3, the other reactants are. . 1) C 6 H 6 + NH 3 2) C 6 H 6 + CH 4 4) C 6 H 6 + CH 3 COCl 3) C 6 H 6 + CH 3 Cl Solution : C 6 H 6 + CH 3 Cl Anhy. Al. Cl 3 C 6 H 5 CH 3 + HCl

AROMATIC HYDROCARBONS LEVEL - I 49) Which of the following will be most easily attacked by an electrophile… 1) 2) 3) 4) Solution : +M effect of -OH group

AROMATIC HYDROCARBONS LEVEL - I 50) In halogenation of aromatic compounds, catalyst is… 1) Lewis base 2) Fe. Cl 3 3) Al. Cl 3 4) Fe. Cl 3 or Al. Cl 3

AROMATIC HYDROCARBONS LEVEL - I 51) When benzene is heated with a mixture of conc. HNO 3 & conc. H 2 SO 4 at 1000 C, the compound formed is … 1) Nitrobenzene 2) o-Dinitrobenzene 3) m-Dinitrobenzene 4) p-dinitrobenzene Solution : C 6 H 6 + HNO 3 Con. H 2 SO 4, <600 C C 6 H 5 NO 2 + H 2 O

AROMATIC HYDROCARBONS 52) Nitration mixture is ……. . 1) 1 : 1 of conc. HNO 3 & conc. HCl 2) 1 : 1 of conc. HNO 3 & conc. H 2 SO 4 3) 1 : 1 of conc. HNO 2 & conc. H 2 SO 4 4) 1 : 10 of conc. H 2 SO 4 & conc. HNO 3 LEVEL - I

AROMATIC HYDROCARBONS LEVEL - I Thank you…