organic reactions

Question 1

alkane and oxygen reaction

Answer 1

excess of oxygen
forms carbon dioxide and water
combustion reaction

Question 2

alkane and halogen reaction

Answer 2

UV light
halogenoalkane formed
free radical substitution

Question 3

halogenoalkane and sodium hydroxide (aq) reaction

Answer 3

heat under reflux
alcohol and halide ion formed
nucleophilic substitution/hydrolysis reaction

Question 4

halogenoalkane and CN-

Answer 4

heat under reflux, ethanolic
halide ion and nitrile formed
nucleophilic substitution

Question 5

halogenoalkane and ammonia reaction

Answer 5

heat, ethanolic
amine and ammonium halide salt formed
nucleophilic substitution

Question 6

what does heating under reflux ensure

Answer 6

no volatile reactants are lost

Question 7

why are some substitution reactionswith done in ethanolic conditions

Answer 7

otherwise an alcohol would form instead of the desired product

Question 8

how to form an amine from an ammonium salt

Answer 8

add sodium hydroxide

Question 9

halogenoalkane and sodium hydroxide (ethanolic) reaction

Answer 9

hot, ethanolic
elimination reaction
alkene forms

Question 10

which alcohols are more likely to undergo substitution and which are more likely to undergo elimination

Answer 10

primary- substitution
tertiary- elimination

Question 11

do higher temperatures favour elimination or substitution

Answer 11

elimination

Question 12

reaction for depletion of ozone

Answer 12

uv light present in upper atmosphere
Cl. +O3 –> ClO. + O2
ClO. + O3 –> Cl. + 2O2

free radical is regenerated
chain reaction

Question 13

how do chlorine radicals form

Answer 13

homolytic fission of chlorine with uv light

Question 14

alkene and sulfuric acid reaction

Answer 14

conc. sulfuric acid
alkyl hydrogen sulfate formed
electrophilic addition

Question 15

what is formed when alkyl hydrogen sulfate is heated

Answer 15

alcohol

Question 16

what determines which product is formed from unsymmetrical alkenes

Answer 16

the stability of the intermediate carbocation

Question 17

alkene and HBr reaction

Answer 17

HBr gas
bromoalkane formed
electrophilic addition

Question 18

alkene and bromine reaction
uses of this reaction

Answer 18

bromine liquid or bromine water
dibromoalkane formed
electrophilic addition
useful to test for alkene

Question 19

alkene and steam reaction

Answer 19

heat and phosphoric acid catalyst
alcohol formed
electrophilic addition/ acid-catalysed hydration

Question 20

what acts as an electrophile in the electrophilic addition reaction of alkene to alcohol

Answer 20

H3O+ (formed from water and acid catalyst)

Question 21

fermentation reaction

Answer 21

yeast present, warm, anerobic conditions
ethanol and carbon dioxide formed from glucose

Question 22

why is yeast needed and warm, anerobic conditions for glucose fermentation

Answer 22

yeast- organism which carries out anerobic respiration of glucose
warm- optimum temperature for enzye action
anerobic- so yeast don’t respire anerobically

Question 23

why does fermentation of glucose stop after a certain point and how can this be prevented

Answer 23

yeast are killed
prevented by distilling the ethanol off

Question 24

alcohol and acidified potassium dichromate reaction

Answer 24

heat, acid catalyst
primary alcohol -> aldehyde (when distrilled) -> carboxylic acid (under reflux)
secondary alcohol -> ketone
oxidation reaction

Question 25

alcohol and conc. acid catalyst

Answer 25

conc. sulfuric/ phosphoric acid catalyst alkene formed elimination/ dehydration reaction

Question 26

reduction of aldehydes/ketones reaction

Answer 26

NaBH4 reducing agent provides H- ions aldehydes- forms a primary alcohol ketones- forms a secondary alcohol

Question 27

aldehyde/ ketone and KCN reaction

Answer 27

KCN in sulfuric acid forms a hydroxynitrile may form a racemic mixture of 2 entaniomers in equal amounts

Question 28

carboxylic acid plus metal (e.g zinc) reaction

Answer 28

carboxylic acid salt (zinc carboxylate) plus hydrogen formed

Question 29

carboxylic acid and alcohol reaction

Answer 29

heat under reflux, conc. sulfuric acid catalyst ester formed reversible reaction condensation/ esterification reaction

Question 30

why is an acid catalyst needed for esterification reaction

Answer 30

reaction is reversible so acid catalyst pushes eqm right to form more ester

Question 31

ester hydrolysis reaction

Answer 31

warm, aqueous dilute acid or alkali plus ester forms carboxylic acid and alcohol

Question 32

acyl chloride and water reaction

Answer 32

forms carboxylic acid and HCl nucleophilic addition-elimination

Question 33

acyl chloride and alcohol reaction

Answer 33

ester and HCl formed nucleophilic addition-elimination

Question 34

acid anhydride plus water reaction

Answer 34

carboxylic acid formed addition-elimination

Question 35

acid anhydride and alcohol reaction

Answer 35

forms ester and carboxylic acid addition-elimination

Question 36

benzene plus nitric acid reaction

Answer 36

conc. nitric acid and conc. sulfuric acid catalyst forms nitrobenzene electrophilic substitution/ nitration reaction

Question 37

formation of nitronium ion reaction

Answer 37

HNO3 + H2SO4 --> H2NO3+ + HSO4- H2NO3+ --> NO2+ + H2O overall eqn. : HNO3 + 2H2SO4 --> +NO2 + 2HSO4- + H3O+

Question 38

benzene and acyl chloride reaction

Answer 38

warm, AlCl3 catalyst forms aromatic ketone electrophilic substitution/ friedel crafts acylation

Question 39

formation of the acylium ion reaction

Answer 39

RCOCl + AlCl3 --> [RCO]+ + [AlCl4]-

Question 40

nitrile reduction reaction

Answer 40

nitrile reducing agent- LiAlH4 and dry ether catalyst/ hydrogen gas and nickel catalyst forms an amine reduction/ hydrogenation reaction

Question 41

why does dry ether need to be used with LiAlH4

Answer 41

else it reacts violently with water

Question 42

nitroarene reduction reaction

Answer 42

add nitroarene, HCl (and NaOH) Tin (Sn) catalyst aromatic arene formed reduction reaction

Question 43

forming polyester reaction

Answer 43

dicarboxylic acid and diol forms a polyester condensation polymerisation

Question 44

forming polyamide reaction

Answer 44

dicarboxylic acid and diamine forms polyamide condensation polymerisation

Question 45

amino acid condensation reaction

Answer 45

forms a polyamide/ polypeptide

Question 46

removal of sulfur dioxide eqn

Answer 46

SO2 + CaO --> CaSO4

Question 47

lithium half cell eqn.

Answer 47

Li+ + e- ⇌ Li E⦵ = -3.04V CoO2 + Li+ + e- ⇌ LiCoO2 E⦵ = +0.56 V