Consider the two structures below and answer all the questions:

A		B
Caffeine, a central nervous system (CNS) stimulant		Ibuprofen, a non-steroidal anti-inflammatory drug

Question 1)Reproduce the structures and indicate the hybridisation states (e.g. sp, sp², sp³) of each of the carbon atoms in both compound A and compound B.

QUESTION 2)Caffeine is known as an alkaloid. It is poorly soluble in cold water. Give the definition of an alkaloid (citing the source used) and suggest a simple chemical treatment that would help solubilise caffeine in water.

question 3) Reproduce compound B of Figure Q1 and label with a * the chiral carbon.

QUESTION 4) Redraw the 3D structure of B, then circle and label the groups around the chiral centre according to the Cahn-Ingold-Prelog (CIP) priority rules. Assign the resulting R or S stereodescriptor to the chiral centre.

QUESTION 5) Draw the 3D structure of the mirror image of the ibuprofen structure on Figure Q1

QUESTION 6 Ibuprofen is fact given as a 1:1 mixture of both R and S stereoisomers. Suggest an experimental technique that can be used to verify whether a tablet contains equal amounts of those isomers. What is such a mixture called?