Reaction Pathways

Question 1

Alkane -> Halogenoalkane

Answer 1

Substitution, Halogen + UV light

Question 2

Alkene -> Alkane

Answer 2

Hydrogenation (addition), H2 and Pd/C

Question 3

Alkyne -> Alkane

Answer 3

Hydrogenation (addition), H2 and Pd/C

Question 4

Alkene -> Dihalogenoalkane

Answer 4

Halogenation (addition), room temperature, alkene + halogen

Question 5

Alkene -> Halogenoalkane

Answer 5

Hydrohalogenation (addition), room temperature, alkene + HX

Question 6

Alkene -> Alcohol

Answer 6

Hydration (addition), steam, dilute H2SO4, 300C, 60atm

Question 7

Alkyne -> Ketone

Answer 7

Hydration (addition), dilute H2SO4, Hg2+

Question 8

Alcohol + O -> Combustion

Answer 8

Complete: excess of O produces CO2 + H20
Incomplete: oxygen deficiency so produces CO or C + H2O

Question 9

Alcohol -> Alkene + Water

Answer 9

Dehydration, concentrated H2SO4, redux/heat

Question 10

Alcohol + HX -> Halogenated compound + water

Answer 10

Substitution with hydrogen halide, concentrated aqueous HX and ZnX2, works best with 3rd degree alcohols

Question 11

1st Alcohol -> Aldehyde -> Carboxylic acid

Answer 11

Oxidation, H2SO4/acidified, K2Cr2O7/KMnO4, reflux

Question 12

1st Alcohol -> Aldehyde

Answer 12

Oxidation, PCC

Question 13

2nd Alcohol -> Ketone

Answer 13

Oxidation, H2SO4/acidified, K2Cr2O7/KMnO4. Reflux

Question 14

Aldehyde -> Carboxylic acid

Answer 14

Oxidation, Tollens’ reagent/ acidified dichromate

Question 15

Alkanoic acid + Alkanol -> Ester + Water

Answer 15

Esterification/condensation, concentrated H2SO4, reflux

Question 16

Haloalkane -> Alcohol + hydrogen halide

Answer 16

Substitution, dilute KOH, reflux

Question 17

Alkyne -> Alkene

Answer 17

Hydrogenation, Lindlar catalyst, H2

Question 18

Fermentation reaction (conditions + energy usage)

Answer 18

C6H12O6(s) -> 2C2H5OH(aq) + 2CO2(g). Temperature ~35C, yeast, anaerobic environment, pH ~4. Produces in aqueous solution so takes a lot of energy to distill