CARBONYL COMPOUNDS and THEIR OXIDATION Flashcards
1
Q
define the term electronegativity
A
measure of the attraction of the bonded atoms to the pair of electrons in the covalent bond
2
Q
what do aldehydes and ketones have in common
A
they both contain the carbonyl functional group,C=0
3
Q
what colour change occurs when alcohols are oxidised by pottasium dichromate
A
pottasium dichromate(V1) is reduced to chromium(111),solution turns from orange to green
4
Q
how is the sigma bond and pi bond in a carbonyl group formed
A
- sigma bond is formed by overlapping of orbitals between carbon and oxygen atoms
- pi bond is formed by the overlap of p orbitals in the carbon and oygen atoms
5
Q
why doesnt a carbonyl bond not react the same way as a double bond
A
- because oxygen is more electronegative than carrbon atom in the carbonyl bond
- this creates a dipole on the C=O bond because the bonded electrons are attracted toward the oxygen
6
Q
describe the oxidation of primary alcohols to form aldehydes and carboxylic acids,using the example of ethanol
A
- Methanol is oxidised to methanal by pottasium dichromate
- to prevent further oxidation,an aldehyde must be distilled.
- however when making a carboxylic acid the reaction mixture is heated under refulx
7
Q
describe the oxidation of secondary alcohols using the example of propanone
A
- ketones cannot be oxidised any further
