3.3 Aldehydes and Ketones

Question 1

What identifies Aldehydes and Ketones?

Answer 1

The contain a carbonyl group (double bonded oxygen)

Aldehyde - At the end (terminal)
Ketone - in the middle (Mid-chain)

Question 2

Suffix for aldehyde

Answer 2

-al

Question 3

Suffix for Ketone

Answer 3

-one

Question 4

Which oxidising agent will exclusively oxidise aldehydes?

Answer 4

Tollen’s reagent - solution of ammoniacal silver nitrate

AgNo3 // NH4

Question 5

What is the spectator ion in Tollen’s Reagent?

Answer 5

ammonia - NH4 which makes the solution basic
It is important to stabilise the silver cation

And nitrate. The only active ingredient is silver (Ag)

Question 6

What is the colour change associated with tollen’s reagent?

Answer 6

The Ag+ will reduce to form a silver mirror and this is the observable colour change

EQUATION:
Ag+ + e -> Ag

Question 7

Tollen’s Reagent - acidic conditions

Answer 7

Aldehyde to carboxylic acid

Question 8

Tollen’s Reagent - neutral conditions

Answer 8

Aldehyde to carboxylic acid

Question 9

Tollen’s Reagent - basic conditions

Answer 9

Aldehyde to carboxylic acid to carboxylate ion