Question

1.       Consult the Material Safety Data Sheets (MSDS) for caffeine, available on line, to be aware of the potential hazards.

2.       How is the caffeine extracted for the tea?

3.       How is the extracted caffeine precipitated from solution?

4.       In the experimental procedure for this laboratory exercise, which piece of equipment is most appropriate to measure:

a)       Volume of water

b)      Volume of the propanol added

c)       Mass of the caffeine

Answer 1

1) potential hazards to be awared by using caffeine are:

Increased risk of heart attacks , may raise blood pressure,indigestion, insomnia etc...

2) intially first tea leaves are poured in hot water but intially tea leaves contains insoluble materials and by ppurpou it into hot water these insoluble materials will be extracted out and hot solution is allowed to cool in that solution we contain both tannins and caffeine and into separate caffeine these solution is passed out with na2co3 and caffeine gets extracted.

3) for precipitating extracted Caffeine need to add around 5-8ml of acetone and transfer the solution to Erlenmeyer flask for recrystallization, and also add some amount of petroleum ether to reach the cloud point and if you don't get a precipitate you have to add more acetone.

4)mass of caffeine as it settled down at end .