Topic 25: Isomerism

Question 1

Chiral

Answer 1

A carbon atom with​ four different groups ​bonded around it so there is ​no line of symmetry ​to the molecule

Question 2

Optical isomers

Answer 2

Molecules that are non-superimposable mirror images of each other and they are not identical. Optically active.

Question 3

Drawing enantiomers

Answer 3

Tetrahedral structures, keep top the same left to right, right to left mirror images.

Question 4

Enantiomers

Answer 4

A pair of molecules that exist in two forms that are mirror images of one another but cannot be superimposed one upon the other

Question 5

Test for enantiomers

Answer 5

Plane polarised light passed through two solutions containing same conc. of each enantiomer.
One will rotate at a specific angle clockwise (+) other at the same angle anticlockwise (-).

Question 6

Racemate

Answer 6

Equal mixture of both enantiomers so no rotation, not optically active as they cancel out.

Question 7

Mechanism of making a chiral molecule part 1

Answer 7

Nucleophilic addition
From ethanal
Partial charges on c and o
Arrow from :CN- to carbon
Arrow from double bond to oxygen
New molecule with positively charges oxygen with lone pair
Arrow from lone pair to H+

Question 8

Making a chiral molecule part 2

Answer 8

Add HCl and water in hydrolysis reaction
Replaces CN with COOH
Makes NH4Cl

Question 9

What goes on the carbon to show chirality?

Answer 9

*