Chapter 26 - Compounds containing the carbonyl group Flashcards
1
Q
Describe the carbonyl group
A
C=O
* Ketones
* Aldehydes
* Carboxylic acids
* Esters
2
Q
Describe the boiling point of carbonyl compounds
A
- C=O is strongly polar
- So all carbonyl’s have dipole-dipole forces
- Higher b.p than alkanes
- Lower b.p than alcohols because alcohols have hydrogen bonding
3
Q
Describe the solubility of carbonyl compounds in water
A
- Shorter chain aldehydes and ketones mix completely with water
- Hydrogen bond forms between O on carbonyl group and water
- As length of C chain increases, become less soluble
4
Q
Describe the reactivity of carbonyl compounds
A
- C=O bond is very polar so reacts
- Typically, nucleophilic additions
5
Q
Describe the Fehling’s test
A
- Warm with aldehyde
- Blue -> Brick red
No reaction with ketones
6
Q
Describe the silver mirror test
A
- Warm with aldehyde
- Silver mirror forms
No reaction with ketones
7
Q
Describe the solubility of carboxylic acids in water
A
- Up to 4C chain are completely soluble
- Can for hydrogen bonds with water
8
Q
Describe the melting points of carboxylic acids
A
- Form hydrogen bonds with each other (even when solid)
- Much higher mp than alkanes
9
Q
Describe the smell of esters
A
Sweet, fruity smells
10
Q
Describe the uses of glycerol (propane-1,2,3-triol)
A
- Attracts water so can prevent creams from drying out
- Solvent in food and medicines
- Plasticiser
11
Q
Describe the advantages of using ethanoic anhydride instead of ethonoyl chloride as an acylating agent
A
- Cheaper
- Less corrosive
- Does not react with water as readily
- Safer (the byproduct is ethanoic acid rather than hydrogen chloride)
12
Q
Describe reflux
A
- Mix of liquids is heated to boiling point for a prolonged period of time
- Vapour is formed which escapes from the liquid mixture, is changed back into liquid and returned to the liquid mixture
- Important to ensure all reactants that evaporate initially can also be oxidised
