A2 Carbonyl qualities

Question 1

c=o bond is

Answer 1

polar

Question 2

what happens when it is polar

Answer 2

is has a permanent dipole-dipole

Question 3

is c=o groups vs alkanes have higher boiling points

Answer 3

c=o

hydrogen bonding can take place

Question 4

c=o solubility

Answer 4

short can c=o can dissolve in water
this is because they can form hydrogen bonds with water
longer alkane vchains have lowered solubility

Question 5

c=o characteristics

Answer 5

The C=O bond in carbonyl compounds is strong and reactive.
This is because of the big difference in electronegativity between carbon
and oxygen makes the cll+=oO- strongly polar. So, nudeophilic reagents
can attack the ell+. Also. since they contain a double bond, carbonyl
compounds are unsaturated and addition reactions are possible.

Question 6

what can oxidise further

Answer 6

only aldehydes
this is because in ketones a c-c bond must be broken in order to be oxidised further, this needs very strong oxidization reagants

Question 7

what test can distingish from aldehydes to ketones

Answer 7

fehlings

sliver mirror

Question 8

fehlings

Answer 8

fehlings a - contains cu2+

fehlings b-alkali and a complexing agent.

Question 9

what happens during the fehlings reaction?

Answer 9

When an aldehyde is warmed with Fehling’s solution, a brick red precipitate of copper(!) oxide is produced as the copper(II) oxidised

the aldehyde is reduced to a carboxylic acid, and is itself reduced to copper( I).

• Ketones give no reaction to this test.

Question 10

potassium dichromate

Answer 10

heat potassium dichomate and the aldehyde under reflux with distillation apparatus to form a carboxylic acid

Question 11

sliver mirror ion

Answer 11

tollens reagent - [Ag(NH3)2]+

Question 12

what happens in tollens test

Answer 12

aldehyde is reduces and sliver is oxides to form a sliver

Question 13

halogenoalkane

R-X

Answer 13

1. add NaOH(aq) and warm
2. acidify with HN03
3. add AgNO~(aq)