WM 2 - Organic Reactions

Question 1

What will phenol not react with?

Answer 1

• Carbonates: although it is acidic, it will not react with carbonates as they are weak alkalis
• Carboxylic acid: phenol will only form an ester when reacting with an acid anhydride

Question 2

How do you test for phenol?

Answer 2

Add neutral Iron (III) Chloride solution, if phenol is present a purple colour should form

Question 3

Give the reactants and reaction conditions for:
Alcohol —> Ester

Answer 3

Carboxylic acid with conc. H2SO4
OR acid anhydride
(Condensation reaction)

Question 4

Give the reactants and reaction conditions for:
Primary alcohol —> Aldehyde

Answer 4

K2Cr2O7 with H2SO4
Under distillation
(Oxidation reaction)

Question 5

Give the reactants and reaction conditions for:
Primary alcohol/Aldehyde —> Carboxylic acid

Answer 5

K2Cr2O7 with H2SO4
Under reflux
(Oxidation reaction)

Question 6

What colour change can be seen when an organic compound is oxidised by acidified potassium dichromate (VI)?

Answer 6

Orange to green

Question 7

Give the reactants and reaction conditions for:
Secondary alcohol —> Ketone

Answer 7

K2Cr2O7 with H2SO4
Under reflux
(Oxidation reaction)

Question 8

Give the reactants and reaction conditions for:
Alcohol —> Alkene

Answer 8

Concentrated H2SO4
Heat under reflux
(Dehydration reaction)

Question 9

Give the reactants and reaction conditions for:
Alcohol —> Haloalkane

Answer 9

Phosphorus (III) Halide
Under reflux
OR Sodium Halide with H2SO4
Under reflux
(Substitution reactions)

Question 10

What is the principle of waste prevention?

Answer 10

It is better to prevent the production of waste than to deal with it after it has been created

Question 11

Why is high atom economy better for the environment?

Answer 11

• Less waste is produced from the reaction which minimises damage from waste chemicals to the environment
• Less raw materials can be used which is more sustainable

Question 12

What is the principle of less toxic syntheses?

Answer 12

Syntheses should be designed to have the least amount of toxic substances produced or used

Question 13

What is the principle of safer solvents?

Answer 13

Syntheses should be designed to minimise the use of solvents and separating agents that are dangerous

Question 14

How can energy use be made more efficient in reactions?

Answer 14

Syntheses should be conducted at room temperature and pressure whenever possible. The use of electricity should be minimised and the source of the electricity should be assessed (whether renewable or not)

Question 15

Why are catalysts environmentally friendly?

Answer 15

Catalysts reduce the need for heating in a reaction which reduces the amount of energy used for reaction