14 Optical Isomerism, Aldehydes & ketones, carboxylic acids

Question 1

What is optical isomerism?

Answer 1

A molecule with an asymmetric C, that forms stereoisomers that differ in their effect on plane polarised light.

Question 2

Racaemic Mixture (Racemate):

Answer 2

A mixture of equal proportions of enantiomers, optically inactive.

Question 2

Chiral C:

Answer 2

C with 4 different R groups (so cannot have double or triple bonds)

Question 3

Enantiomers:

Answer 3

Two different forms of an optically active molecule, non-superimposable mirror images.

Question 4

Why does a Racemate form? What does optically inactive mean?

Answer 4

Carbonyl group is planar, Nu addition can take place above and below the plane.

Any rotation of PPL by one enantiomer is cancelled out by the other.

Question 5

Carboxylic Acids: why are they soluble?

Answer 5

Can form H bonds with H2O.

Question 6

Esters: how to reverse esterification.

Answer 6

Acid hydrolysis:
products –> alcohol + carb acid

Base hydrolysis:
products –> alcohol and carboxylate ion.

Question 6

How to make Soap.

Answer 6

Ester and 3 NaOH –> Glycerol and sodium salts.

Question 7

IUPAC for glycerol.

Answer 7

Propan-1,2,3-triol

Question 8

Properties of Esters:

Answer 8

Sweet smelling
Low BP
Good solvents for polar molecules.

Question 9

How to make biodiesel.

Answer 9

Ester and 3 methanol –> Glycerol and methyl esters.

Question 10

Reactions with Acid anhydrides and X produce?

Answer 10

X and Carboxylic acid

Question 10

Reactions with Acyl chlorides and X produce?

Answer 10

X and HCL