a. (CH 3 ) 2 CHCH(Cl)CH 3 b. CH 3 CH 2 CH(CH 3 )CH(C 2 H 5 )Cl c. CH 3 CH 2 C(CH 3 ) 2 CH 2 I d. (CH 3 ) 3 CCH 2 CH(Br)C 6 H 5.

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1 1. Name the following halides according to IUPAC system and classify them as alkyl, allyl, benzyl (primary, secondary, tertiary), vinyl or aryl halides: a. (CH 3 ) 2 CHCH(Cl)CH 3 b. CH 3 CH 2 CH(CH 3 )CH(C 2 H 5 )Cl c. CH 3 CH 2 C(CH 3 ) 2 CH 2 I d. (CH 3 ) 3 CCH 2 CH(Br)C 6 H 5. a. 2-chloro-3-methyl butane (sec) b.3-chloro-4-methyl-hexane[sec] c. 1- ido-2, 2-dimethyl butane d. 1-bromo 3,3-dimethyl-1-phenyl-butane[sec,,benzylic] 2. Name the following halides according to IUPAC system and classify them as alkyl, allyl, benzyl (primary, secondary, tertiary), vinyl or aryl halides: a. CH 3 CH(CH 3 )CH(Br)CH 3 b. CH 3 C(C 2 H 5 ) 2 CH 2 Br c. CH 3 C(Cl)(C 2 H 5 )CH 2 CH 3 d. CH 3 CH=C(Cl)CH 2 CH(CH 3 ) 2. a. 2-bromo-3-methyl butane (sec) b. 1-bromo-2-ethyl-2-methyl-butane[pri] c. 3-chloro-3-methyl-pentane[ter] d. 3-chloro-5-methyl-hex-2-ene[vinylic] 3. Name the following halides according to IUPAC system and classify them as alkyl, allyl, benzyl (primary, secondary, tertiary), vinyl or aryl halides: 1

2 a. CH 3 CH=CHC(Br)(CH 3 ) 2 b. p-clc 6 H 4 CH 2 CH(CH 3 ) 2 c. m-clch 2 C 6 H 4 CH 2 C(CH 3 ) 3 d. o-br-c 6 H 4 CH(CH 3 )CH 2 CH 3. a. 4-bromo-4-methyl- pent-2-ene [allylic] b. 1-chloro-4-(2-methyl propyl ) benzene(aryl) (sec) c. 1-chloro methyl-3-(2,2-dimethyl propyl)benzene [benzylic]) d. 1-bromo-2(1-methyl propyl) benzene.[aryl] 4. Give the IUPAC names of the following compounds: CH 3 CH(Cl)CH(Br)CH 3 CHF 2 CBrClF ClCH 2 C ßCCH2Br. 2-bromo-3-chloro-butane 1-bromo,1-chloro,1,2,2-tri fluoro ethane 1-bromo-4-chloro-but-2-yne 5. Give the IUPAC names of the following compounds: (CCl 3 ) 3 CCl CH 3 C(p-ClC 6 H 4 ) 2 CH(Br)CH 3 (CH 3 ) 3 CCH=ClC 6 H 4 I-p. i 2-(trichloro methyl)-1,1,1,2,3,3,3-hepta chloro propane. ii 2-bromo 3,3-bis( p- chloro phenyl) butane iii 1-chloro-1-(4-iodo phenyl) -3,3-dimethyl-but-1-ene. 2

3 6. Write the structures of the following organic halogen compounds. 2-Chloro-3-methylpentane p-bromochlorobenzene 1-Chloro-4-ethylcyclohexane iv. 2-(2-Chlorophenyl)-1-iodooctane. 7. Write the structures of the following organic halogen compounds. Perfluorobenzene 4-tert-Butyl-3-iodoheptane 1-Bromo-4-sec-butyl-2-methylbenzene v 1,4-Dibromobut-2-ene. 3

4 iv.. 8. Which one of the following has the highest dipole moment? CH 2 Cl 2 CHCl 3 CCl 4. CH 2 Cl 2 9. A hydrocarbon C 5 H 10 does not react with chlorine in dark but gives a single monochloro compound C 5 H 9 Cl in bright sunlight. Identify the hydrocarbon. The higher alkanes do not react in dark, but in ultraviolet light or higher temperature gives monochloro derivative as main product. Pentene or chlorination in presence of sunlight gives monohalogen derivative. 10. Write the isomers of the compound having formula C 4 H 9 Br. a. - 1-bromobutane b. - 1-bromo-2-methyl propane 4

5 c. - 2-bromo- 2-methyl propane d. - 2-bromobutane. 11. Write the equations for the preparation of 1-iodobutane from (i) 1-butanol (ii) 1-chlorobutane (iii) but-1-ene. (i) (ii) (iii). 12. What are ambident nucleophiles? Explain with an example. The nucleophiles with two nucleophilic centers are called ambident nucleophile. They can react through either of these centers. Depending on the reagent and the reaction conditions; the reaction may take place predominantly at one of these centers. Examples are C N (reagent KCN, AgCN) etc Nitrite O = N O - (KNO 2, AgNO 2 ). 13. Which compound in each of the following pairs will react faster in S N 2 reaction with OH? CH 3 Br or CH 3 I (CH 3 ) 3 CCl or CH 3 Cl. 5

6 Methyl iodide is more reactive than methyl bromide as iodide is a better leaving group. 14. Predict all the alkenes that would be formed by dehydrohalogenation of the following halides with sodium ethoxide in ethanol and identify the major alkene: 1-Bromo-1-methylcyclohexane 2-Chloro-2-methylbutane 2,2,3-Trimethyl-3-bromopentane. 1 - methyl cyclohexene 2 - methyl but-2-ene 3,4,4-trimethyl-pent-2-ene 15. How will you bring about the following conversions? Ethanol to but-1-yne Ethene to bromoethane Propene to 1-nitropropane iv. Toluene to benzyl alcohol v. Propene to propyne. 6

7 v v. 16. How will you bring about the following conversions? Ethanol to ethyl fluoride Bromomethane to propanone But-1-ene to but-2-ene iv. 1-Chlorobutane to n-octane v. Benzene to biphenyl. iv. 7

8 v. 17. Explain why The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride? Alkyl halides, though polar, are immiscible with water? Grignard reagents should be prepared under anhydrous conditions? The low dipolemoment of chlorobenzene is due to resonance phenomenon. The polarity and hence dipole moment is due to resonance effect as a result the transmission of π - electron in conjugate π - bonds is very little. Where as there is no resonance in cyclohexyl chloride, but the polarity and hence dipolemoment is due to induction effect which is more. All the halogen derivatives of hydrocarbon are polar in nature but they are insoluble in water, because they are unable to form hydrogen bond with water to break the hydrogen bond already present in water. They are soluble in organic solvents. Grignard reagent should be prepared under anhydrous conditions, because it is very reactive. It reacts very quickly with any source of proton to give hydrocarbon. It reacts with water very quickly. Therefore, it is necessary to avoid moisture from the Grignard reagents. 18. Give the uses of Freon 12, DDT, carbon tetrachloride and iodoform. Freon12 a) It is used as a refrigerant (cooling agent) in refrigerators and air conditioners, b) It is also used as a propellant in aerosols and foams to spray out deodorants, cleaners, hair sprays, shaving creams and c) It is also used as insecticides. Carbon tetrachloride a) It is used as a solvent for oils, fats and waxes. b) It is used as a fire extinguisher under the name pyrene. 8

9 c) It is used as dry cleaning. Iodoform a) It is used as antiseptic and this nature is due to iodine that it liberates. b) It is used in the manufacture of pharmaceuticals. 19. Write the structure of the major organic product in each of the following reactions: iv. iv. 20. Write the structure of the major organic product in each of the following reactions: 9

10 iv. iv. 21. Write the mechanism of the following reaction: nbubr + KCN nbucn EtOH H 2 O n-bubr is a primary halide Undergoes nucleophilic substitution by SN 2 mechanism CN - appraoaches the carbon atom from the side opposite at the halogen atom and forms a covalent bond and at the same time Br leaves as Br - The transition state is The nucleophiles, Nu - approaches the carbon atom on the side opposite from the halogen and forms new covalent bond with the carbon of the group C-X as the displaced base, X -, leaves Nu - + R-X slow Nu.R.X fast 10

11 Nu R + X - RX + KCN transition state RC = N + KX This is because KCN is an ionic compound, K + [CN - ], Since carbon carrying a lone pair of electrons is more reactive than nitrogen carrying a lone pair, the transition state is formed by the carbon of the cyanide ion forming band with the carbon of the C-X. 22. Arrange the compounds of each set in order of reactivity towards S N 2 displacement: 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 3-Bromo-2- methylbutane 1- Bromobutane, 1-Bromo-2,2-dimethylpropane, 1-Bromo-2- methylbutane, 1-Bromo-3-methylbutane. 1-Bromopentane, 2-Bromopentane, 2-Bromo-2-methylbutane,[ in decreasing order] ii.1-bromo-3-methyl butane, 2-bromo- 3 methyl butane,2-bromo-2-methyl-butane 1- Bromobutane, 1-Bromo-3-methyl-butane,1-bromo-2-methyl-butane,1-bromo- 2,2 dimethyl propane. 23. Out of C 6 H 5 CH 2 Cl and C 6 H 5 CHClC 6 H 5, which is more easily hydrolysed by aqueous KOH. C 6 H 5 CH 2 Cl is a primary halide and undergoes hydrolysis bysn 2 mechanism. C 6 H 5 CHClC 6 H 5 undergoes hydrolysis by SN 1 or SN 2 mechanism. Though the carbocation in this case is more stable, there is steric hindrance and hence SN 2 mechanism is followed and the first one is more readily hydrolysed. 24. p-dichlorobenzene has higher m.p. and solubility than those of o- and m-isomers. Discuss. The melting of p-isomer is quite higher than ortho and meta isomer. This is due to the fact that it has symmetrical strcture and therefore its molecules can be easily packed closely in crystal lattice. As a result, intermolecular forces of attraction are stronger and therefore greater energy is required to break its lattice and it melts at higher temperature. 11

12 25. The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain. Aqueous KOH contains only OH - ions, which acts as nucleophiles and these bring about hydrolysis of alkyl chlorides to the corresponding alchohol. In the case of alcoholic KOH, the ethoxide ion present is a strong base and removes HCl. 26. Primary alkyl halide C 4 H 9 Br (a) reacted with alcoholic KOH to give compound (b). Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), C 8 H 18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions. According to the problem when alkyl bromide (A) was treated with sodium, it gave a compound which is not a straight chain hydrocarbon. Therefore (A) cannot be butyl bromide. It may be isobutyl bromide. The complete reactions are 27. Write structures of the following compounds: 2-Chloro-3-methylpentane 1-Chloro-4-ethylcyclohexane 4-tert. Butyl-3-iodoheptane 12

13 iv. 1,4-Dibromobut-2-ene v. 1-Bromo-4-sec. butyl-2-methylbenzene. iv. v. 28. Why is sulphuric acid not used during the reaction of alcohols with KI? H 2 SO 4 cannot be used along with KI in the conversion of an alcohol to an alkyl iodide as it converts KI to corresponding HI and then oxidises it to I Write structures of different dihalogen derivatives of propane. ClCH 2 CH 2 CH 2 Cl ClCH 2 CHClCH 3 Cl 2 CH 2 CH 2 CH 3 iv. CH 3 CCl 2 CH Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields A single monochloride. Three isomeric monochlorides. 13

14 Four isomeric monochlorides. All the hydrogen atoms are equivalent and replacement of any hydrogen will give the same product. The equivalent hydrogens are grouped as a, b and c. The replacement of equivalent hydrogens will give the same product. Similarly the equivalent hydrogens are grouped as a, b, c and d. Thus, four isomeric products are possible. 31. Draw the structures of major monohalo products in each of the following reactions: 4

15 32. Arrange each set of compounds in order of increasing boiling points. Bromomethane, Bromoform, Chloromethane, Dibromomethane. 1-Chloropropane, Isopropyl chloride, 1-Chlorobutane. Chloromethane, Bromomethane, Dibromomethane, Bromoform. Boiling point increases with increase in molecular mass. Isopropyl chloride, 1-Chloropropane, 1-Chlorobutane. Isopropyl chloride being branched has lower b.p. than 1-Chloropropane. 33. In the following pairs of halogen compounds, which compound undergoes faster SN1 reaction? Tertiary halide reacts faster than secondary halide because of the greater stability of tert-carbocation. 34. Write the structure of the major organic product in each of the following reactions 1

16 iv. v. v v v iv. v. v 16

17 v v 35. How can the following conversions be carried out? Propene to propan-1-ol Ethanol to but-1-yne 1-Bromopropane to 2-bromopropane iv.toluene to benzyl alcohol v. Benzene to 4-bromonitrobenzene v Benzyl alcohol to 2-phenylethanoic acid v Ethanol to propanenitrile v Aniline to chlorobenzene ix. 2-chlorobutane to 3, 4-dimethylhexane x. 2-methyl-1-propene to 2-chloro-2-methylpropane x Ethyl chloride to propanoic acid x But-1-ene to n-butyliodide x 2-Chloropropane to 1-propanol xiv. Isopropyl alcohol to iodoform xv. Chlorobenzene to p - nitrophenol xv 2-Bromopropane to 1-bromopropane xv Chloroethane to butane 17

18 xv Benzene to diphenyl xix. tert - Butyl bromide to isobutyl bromide xx. Aniline to phenylisocyanide iv. v. v v V 18

19 ix. x. x x x xiv. 1

20 xv. xv xv xv xix. 20

21 xx. 21

DAV CENTENARY PUBLIC SCHOOL, PASCHIM ENCLAVE, NEW DELHI-87

DAV CENTENARY PUBLIC SCHOOL, PASCHIM ENCLAVE, NEW DELHI-87 (iv) benzene 1 Chloromethyl 3 (2, 2 dimethylpropyl) Q1 Name the following compounds according to IUPAC system. (CH 3 ) 3 CCH 2 CH(Br)C 6 H 5 CH 3 C(C 2 H 5 ) 2 CH 2 Br CH 3 CH=CHC(Br)(CH 3 ) 2 (iv) o-br-c