Aldehydes and Ketones Flashcards Preview

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Flashcards in Aldehydes and Ketones Deck (11):
1

Aldehydes and ketones contain what?

A carbonyl group

2

Where do aldehydes have their carbonyl group?

At the end of the carbon chain- their names end in -al.

3

Where do ketones have their carbonyl group?

In the middle of the carbon chain- their names end in -one, and often have a number to show which carbon the carbonyl group is on.

4

How are aldehydes and carboxylic acids made?

By oxidising primary alcohols.

5

What is often used to oxidise alcohols?

Acidified potassium dichromate (VI)

6

To get just the aldehyde...

you need to get it out of the oxidising solution as soon as it's formed.

7

To produce the carboxylic acid...

the alcohol has to be vigorously oxidised- the alcohol is mixed with excess oxidising agent and heated under reflux.

8

How are ketones made?

By oxidising secondary alcohols.Refluxing a secondary alcohol with acidified dichromate (VI) will produce a ketone.

9

Using a reducing agent you can:

1) Reduce an aldehyde to a primary alcohol.2) Reduce a ketone to a secondary alcohol.You'd usually use NaBH4 dissolved in water with methanol as the reducing agent.

10

What is Brady's reagent used for?

Tests for a carbonyl group.If present, bright orange precipitate forms.

11

What is Tollens' reagent and what is it used for?

It is a colourless solution of silver nitrate dissolved in aqueous ammonia- when heated together in a test tube, the aldehyde is oxidised and Tollens' reagent is reduced causing a silver mirror to form.Distinguish between an aldehyde and ketone.It uses the fact an aldehyde can be easily oxidised to a carboxylic acid, but a ketone can't.