organic ceica eactins · 2020. 9. 13. · organic chemistry 308 g doc scientia - ieb senior...

ORGANIC CHEMICAL REACTIONSUnit

3

307Doc Scientia - IEB Senior Chemistry Answer Book

Exercise 42: Page 372

1. B

2

Reaction General reaction typeSpecific

reaction type

2.1 CH2Cℓ–CH2Cℓ → CH2=CHCℓ + HCℓ Elimination Dehydrohalogenation

2.2 CH2=CH2 + Cℓ2 → CH2Cℓ–CH2Cℓ Addition Halogenation

2.3 CH3CH2OH → CH2=CH2 + H2O Elimination Dehydration

2.4 C2H6 → CH2=CH2 + H2 Elimination Dehydrogenation

2.5 CH3CH2Br + H2O → CH3CH2OH + HBr Substitution Hydrolysis

3.1 Ethane reacts with bromine.

3.2 Propene reacts with hydrogen gas with Pt as catalyst.

3.3 Butane reacts with bromine.

C CH H+ +C C

H H Br

H H H

H H

H

H

Br Br BrH

+ +Br Br BrHH HC CC CC CC C

H HH H

H H

H HH HH HH H

H HH Br

H HC CC CC CH

H H

H HH

H HHH

H HH H

+Pt

ORGANIC CHEMISTRY

308

G

Doc Scientia - IEB Senior Chemistry Answer Book

3.4 Ethene reacts with water that contains concentrated H2SO4 as catalyst.

3.5 1 mol of but-1-ene reacts with water.

4.1 When longer chains of hydrocarbons are divided into shorter chains.

4.2 To obtain a larger percentage of usable products from the heavier fractions of crude oil. OR Shorter chains are mixed with fuel to enrich it. OR Shorter chains burn more evenly.

5.1

5.2 High temperatures and high pressure

5.3 Smaller, more usable molecules are manufactured, which are used in the production of various products.

6.

Propene

C CH H O+C C

H H

H H H

H H

H

H H

OH2SO4

CC CH H+C C C C

H H H HO H

H

HH H H

CH H

H H

H HH

OH2SO4

C C

H

H H

H

HH

+ +

H

H

H

H

C C

H

H

H

H

C C

hexane (C6H14) ethane

high temp.

highpressure

ethene ethene

H C CC C C C

H HH

H

HH HH HH

H H H

H CC C

HH

HH

H


3


7.1

7.2 The ethene released by the banana ages the cabbage and lettuce. OR Lettuce and cabbage will change colour. OR Lettuce and cabbage will go bad and rot.

7.3 CnH2n

7.4 A: Substitution: halogenation/bromination B: Addition: hydrogenation D: Addition: hydration G: Substitution: hydrolysis

7.5

7.6 HBr

7.7.1 E: concentrated and dissolved in ethanol. G: diluted with water.

7.7.2 Dehydrohalogenation

8.1 Contains a double bond between two carbon atoms.

8.2

8.3 Addition: hydrohalogenation

8.4

Propan-2-ol Propan-1-ol

H

H

H

H

C C

C C

H

H H

H

HH

+ H H

H

H

H

H

C CPt

C C CH HOR+C C C CC C

H H HBr HH Br

H H H H

H H H

H H

H HH H

H Br

major product minor product

ORC H

H

C C

HO

H

H

H

H H

major product

C H

H

C C

H HO

H

H

H H

minor product

ORGANIC CHEMISTRY

310

G


8.5 Hydrolysis

8.6.1 Water

8.6.2 H2SO4/H3PO4

8.6.3 Addition: hydration

8.7.1 Propene

8.7.2 Elimination: dehydrohalogenation

9.

3-bromo-3-methylpentane 2-bromo-3-methylpentane

10.1 CH3CHCℓCH3 + NaOH → CH3CHOHCH3 + NaCℓ

10.2 CH2BrCH3 CH2=CH2 + HBr

11.1.1 Substitution: halogenation

11.1.2 Sunlight/heat

11.2

12.1 A: Brown colour disappears and the mixture becomes colourless. B: The colour stays brown at first and does not change immediately.

12.2 Addition: halogenation

12.3 3-chloroprop-1-ene

C

H

C

H

C C HC

CH

H

H HH

H

H BrH HH

C

H

C

H

C C HC

CH

H

H HH

H

Br HH HH

OR

NaOHΔ

C Cℓ

F

Cℓ

F


3


12.4

IUPAC name: 1,2-dibromo-3-chloropropane

12.5 Solution A is unsaturated. There is a double bond between the two C atoms. Solution B is saturated. All C-C bonds are single bonds. Unsaturated compounds are more reactive than saturated compounds.

13.1

13.2

14.1 Substitution

14.2

15.1 P. Q.

C CH H+C C C C

BrCℓ Br Cℓ

H H H H

H H

H H

Br Br

HH CC O CC H H H

HH

O

HH

H

H

H

+H2SO4

H CC OC

HH

H HH

H

H

H

ORH

HH C

C

C

C

C

C

CC C

C

CC H

H

H

H

HH H

H

H

H

HH

HH

Br

Br

HH HH

H

H HH

HBr

+

+

KOH in ethanol

Δ

major product

minor product

C CH H

H H

ethene

C C

H H

H

HOH

H

ethanol

ORGANIC CHEMISTRY

312

G


15.2 Y

15.3 Dehydrohalogenation

15.4 X: Dilute strong base in water, mild heat Y: Concentrated strong base in ethanol, strongly heated.

15.5 P: Alkenes Q: Alcohols

16.1 Heat or light energy must be added.

16.2 Substitution

16.3

bromomethane dibromomethane tribromomethane tetrabromomethane

17.1

17.2

17.3

C Br

H

H

H C Br

Br

Br

HC Br

H

Br

H C Br

Br

Br

Br

C C C H

H

H

H H HPt

H

H

propene propane

addition:hydrogenation+ H CC HC

HH

H HH

H

C HC Cℓ

H

H

H Cℓ

H

H

light energy+ C HC H

H

H

H Cℓ

Cℓ

H

+

chloroethane

substitution:halogenation

C C C CC C H

H H Br H

H H H H

H H HH Br

H

H

+

2-bromopropanepropene

addition:hydrohalogenation

major product


3


17.4

17.5

17.6

17.7

17.8

elimination: dehydrohalogenation

C C C C

H

H

H H

H

HH H

+

1-bromobutane but-1-ene

C CC C

H

H H

H

H H

H

Br

H H NaOH in

ethanol

high heat

H Br

C CC CC CCℓ

H H

H H H

H HH HCℓ

H Cℓ Cℓ

H H

+

propene 1,2-dichloropropane

addition:halogenation

C CC C Na

H

H H

H

H O

H

H

Br

H

H H

+

2-bromobutane butan-2-olsubstitution: hydrolysis

C CC C

H

H H

H

H Br

H

H

H H

+H2O

mildheat

H

Na O

C C C C H

H

H

H H O

H H H

H H

+

butan-2-olbut-2-ene

elimination: dehydration

C CC C

H

H H

H

H

H

HO H

H H

H2SO4

heat

major product

H2SO4(c)C C C H

H

H

H H O

H H

H

+

addition: hydration

C CC

O

H

H

H H

H

HH

H

propenepropan-2-ol

orH3PO4

major product

ORGANIC CHEMISTRY

314

G


18.1

18.2 Propan-2-ol For propan-2-ol, the position of the hydroxyl is in the centre of the molecule, while it is at the end for propan-1-ol. The propan-1-ol molecule has stronger London forces due to its longer non-polar tail, than propan-2-ol has. The net intermolecular forces for propan-1-ol are stronger than for propan-2-ol and the boiling point of propan-2-ol is therefore lower.

18.3 Dehydration

18.4 Propene

18.5 Haloalkanes OR alkyl halides

18.6 Dilute base/NaOH/KOH/aqueous base/NaOH/KOH/NaOH/KOH in water OR H2O

18.7.1 Dehydrohalogenation OR Dehydrobromination

18.7.2 CH3CHBrCH3 CH3CH=CH2 + HBr (Condensed formulae are deduced from the structural formulae.)

18.8 Hydrogenation

18.9

C C C

H H H

H

O HHH

H

C CC

HHH

H

H H

NaOH

C CC

H

H H

H

Br H

H

H

+ +KOH in ethanol

Δ; refluxC C C H NaH

H

H

H O BrO

H H HNa

H

+

C CC CC CH

H H

HH H H

HH HH

H H H

H H

+Pt, Pd, Ni


3


19.1.1 Ethanoic acid

19.1.2 Methylpropane

19.2 Base/basic/alkaline Compound A is acidic – it will neutralise an alkali/a base. Thus, a wasp sting is alkaline (basic).

19.3

20.1 A saturated hydrocarbon contains only carbon and hydrogen and all of the bonds between carbon atoms are single bonds.

20.2 CH3CH2CH=CH2 + H2 CH3CH2CH2CH3

21.1 3-ethylpentane

21.2 Methyl propanoate

22.1

22.2 Addition

22.3

22.4.1 Compounds with the same molecular formula, but different structural formulae

22.4.2 B: Butan-2-ol C: Methylpropan-2-ol

22.4.3 A

22.4.4 The intermolecular forces weaken as the molecule branches, because the surface area and therefore the London forces, decrease. A has no branches, and therefore has the strongest intermolecular forces and also the higher boiling point because more energy is needed to overcome the IMF’s.

+C OC C H C

H HH HH H

H HH HH H

HH HC C O C

O

H2SO4O

H

HC CC C C H

H H HH H H

H H HH H H

H C OC

O

+heat

O H

C CC CCC O

H H H

HH

H HH

H HHH

H HHHH H

+ O

H

H

C CH2SO4

Pt

organic ceica eactins · 2020. 9. 13. · organic chemistry 308 g doc scientia - ieb senior...

Documents