10. Aldehydes and ketones Flashcards Preview

Higher Chemistry 2020-2021 > 10. Aldehydes and ketones > Flashcards

Flashcards in 10. Aldehydes and ketones Deck (15)
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1
Q

What other name are the aldehydes known by?

A

The Alkanals

2
Q

What other name are the ketones known by?

A

Alkanones

3
Q

What is the general formula of aldehydes and ketones?

A

Cn H2n O

4
Q

What functional group do aldehydes and ketones share?

A

The carbonyl group

5
Q

Where is the carbonyl group found in aldehydes?

A

Always on the first C atom.

6
Q

Where is the carbonyl group found in ketones?

A

On an “inside” C atom between 2 alkyl groups.

(alkyl groups represented by R here)

7
Q

How are aldehydes formed?

A
  • oxidation of a primary alkanol
  • reduction of a carboxylic acid
8
Q

How are ketones formed?

A

oxidation of a secondary alkanol

9
Q

How can aldehydes be distinguished from ketones?

A

Aldehydes only will give a positive test with

  • tollen’s reagent
  • fehling’s solution
10
Q

What change is observed with Tollen’s reagent?

A

A silver mirror forms

11
Q

What change is observed with Fehling’s solution?

A

Blue to orange/red

12
Q

What colour change is observed with acidified potassium dichromate solution?

A

Orange to green

13
Q

Why must potassium dichromate solution be acidified?

A

As a source of H+ (aq) ions

14
Q

What reactions do aldehydes undergo?

A
  • ​oxidation to carboxylic acids
  • reduction to primary alkanols
15
Q

What reactions do ketones undergo?

A

reduction to secondary alkanols