Module 6 Organic Chemistry and Analysis

Question 1

What is the carbonyl functional group

Answer 1

C=O

Question 2

Outline aldehydes

Answer 2

-In aldehydes the carbonyl functional group is found at the end of a carbon chain.
-The carbon atom of the carbonyl group is attached to one or two H atoms
-The group is written as CHO

Question 3

Outline methanal

Answer 3

-The simplest aldehyde -HCHO.
-AKA formaldehyde which is used in solution to preserve biological specimens

Question 4

Outline ketones

Answer 4

-The carbonyl functional group is joined to two carbon atoms in the carbon chain. The ketone group is written as CO.

Question 5

Outline propanone

Answer 5

Simplest ketone -CH3COCH3
-AKA acetone used as an important industrial solvent and in nail varnish removers

Question 6

Outline the oxidation of aldehydes

Answer 6

-Can be oxidised to carboxylic acids when refluxed with K2Cr2O7 and dilute sulphuric acid.

Question 7

Why don’t ketone undergo oxidation reactions

Answer 7

Lack of reactivity

Question 8

Outline the C=O bond in carbonyls

Answer 8

-Pi bond above and below the plane of the carbon and oxygen atoms, formed by the sideways overlap of p-orbitals

Question 9

Why do alkenes and carbonyls react differently

Answer 9

-The C=C bond in alkenes is non-polar whereas C=O is polar
-O is more electronegative than C. The electron density in the double bond lies closer to the O atom than to the C. Therefore the O end is slightly negative and the C end is slightly positive.

Question 10

How do carbonyls attract nucleophiles

Answer 10

-A nucleophile is attracted to and attacks the slightly positive C atom, resulting in addition across the C=O Double bond
-Results in nucleophilic addition reactions