WM: Aldehydes And Ketones

Question 1

What do ketones have?

Answer 1

A carbonyl group in the MIDDLE of the chain

Question 2

How do you make an aldehyde?

Answer 2

By oxidising a PRIMARY ALCOHOL

Heat with ACIDIFIED POTASSIUM DICHROMATE as the oxidising agent

You must distil the aldehyde out of the reaction mixture as soon as its formed so that a carboxylic acid is not formed

Question 3

How do you make a ketone?

Answer 3

Reflux a SECONDARY ALCOHOL with an oxidising agent

Question 4

What is refluxing and what does it do?

Answer 4

Heating under reflux, for a period of time gives reactants time to react.

The condenser condenses the vapours and adds them back into the reaction mixture to give them more time to react.

It’s good to make the heating electrical since the reactants and products are often volatile and flammable

Question 5

How do you purify volatile liquids?

Answer 5

Distillation, you know the boiling temp of the thing you want, when the thermometer reaches that temp, open the condenser and collect the liquid that comes out

Question 6

What do aldehydes have?

Answer 6

A carbonyl at the END of the chain

Question 7

How does Hydrogen Cyanide react with carbonyls?

Answer 7

Nucleophilic Substitution.

HCN partially dissociates in water to give H+ and CN-

The CN attacks the partially positive carbon atom and donates a pair of electrons, Two electrons from the double bond transfer to the oxygen

The H bonds to the hydroxyl group