Aliphatic Reactions

Question 1

Alcohols to carboxylic acids

What are the reagents used and state the observations?

Answer 1

Acidified potassium dichromate

Colour changes from orange to green

Question 2

Carboxylic to alcohols

Reagents used?

Answer 2

Lithium tetrahydridoaluminate(LiAlH4) in ethoxyethane

Question 3

Halogenoalkanes to alcohols

Reagent used and mechanism?

Answer 3

Sodium hydroxide(aq) and reflux 
Nucleophilic substitution

Question 4

Alcohols to Halogenoalkanes

Reagents used?

Answer 4

Potassium bromide(KBr) and Concentrated sulphuric acid( H2SO4)
   OR
Hydrochloric acid(HCL) and Zinc chloride(ZnCl2)

Question 5

Alcohols to Aldehydes/ketones

Reagents used and observations?

Answer 5

Acidified potassium dichromate or alkaline potassium manganate(H+/MnO4-)

Colour changes from orange to green in dichromate
Colour changes from purple to colourless in manganate

Question 6

Aldehydes/ketones to Alcohols

Reagent used?

Answer 6

Sodium tetrahydridoborate(NaBH4)
Reduction

Question 7

Aldehydes/ketones to Hydroxynitrile

Reagents used and the mechanism?
What happens when you add the reagents?

Answer 7

Potassium Cyanide(KCN) and sulphuric acid(H2SO4)

Nucleophilic addition reaction

Adding KCN to Aldehydes and ketones extends the carbon chain.

Question 8

Hydroxynitrile to hydroxyacid

Reagent used and the condition?

Answer 8

Dilute Sulphuric acid(H2SO4)

Reflux

Question 9

Carboxylic acids to Esters

Reagents used ?

Answer 9

Alcohol( CnH2n+1OH) and Concentrated Sulphuric acid(H2SO4)

Or

Hydrogen chloride(HCL gas)

Question 10

Carboxylic acids to Decarboxylation(=removal of carbon dioxide)

Reagents used?

Answer 10

Soda lime

Or NaOH ( sodium hydroxide)

Question 11

Carboxylic acids to Amide

Reagent used?

Answer 11

Heat acid or the ammonium salt with urea

Question 12

Amide to Carboxylic acids

Reagent used?

Answer 12

Dilute acid and sodium hydroxide

Hydrolysis reaction

Question 13

Halogenoalkanes to Nitrile

Reagents used?

Answer 13

Potassium cyanide in ethanol

Question 14

Halogenoalkanes to Primary Amine(NH2)

Reagents used and condition?

Answer 14

Heat excess Ammonia in ethanol

Question 15

Nitrile(CN) to Primary Amine(NH2)

Reagent used and type of reaction?

Answer 15

Lithium tetrahydridoaluminate(LiALH4)

Reduction reaction

Question 16

Primary amine to Amine salt

Reagents used?

Answer 16

RXN with acids

Question 17

Primary Amine to Amides

Reagent used?
What is produced when the Amine reacts with the reagent?

Answer 17

Ethanoyl chloride

Peptide linkage is produced when
Amine reacts with an acid chloride(e.g. ethanoyl chloride)

Question 18

Primary Amine to Alcohols

Reagent used?

How is the reagent produced?

Answer 18

Cold nitric acid( HNO3)

The nitric acid is unstable compound so dilute acid(HCL) and sodium nitrite(NaNO3)makes the nitric acid

Question 19

Carboxylic acids to Acid chlorides

Reagent used?

Answer 19

SOCl2 (sulfur dichloride oxide)

Or

PCl3( phosphorus trichloride)

Or

PCl5(phosphorus pentachloride)

Question 20

Amino acids to do/poly peptides

Reaction?

Answer 20

Condensation reaction