CPAC

Question 1

CPAC 4 : Investigating the hydrolysis of halogenoalkanes
Method

Answer 1

Set up water bath at ~50 degrees
Fill 3 test tubes each with 5cm3 of ethanol.
Add 4 drops of iodo-butane to the 1st testube, 4 drops of chloro-butane to the 2nd ….
Label tubes
Loosely place a bung in each & place test tubes in water bath
Add 5cm3 of silver nitrate solution into 3 new test tubes and place in water bath
Once they have reached temp add the silver nitrate and start timer
Measure time taken for precipitate to appear
Repeat for other 2 test tubes

Question 2

CPAC5: Investigate the oxidation of ethanol
Method

Answer 2

Add 20cm3 of acidified sodium dichromate solution to a 50ml pear shaped flask
Cool the flask in a water bath
Set apparatus up for reflux, keeping it in ice bath
Add a few anti bumping granules
Measure our 1cm3 of ethanol and carefully add few drops at a time down the reflux condenser
Allow for reaction to subside after each addition before adding more
When all has been added remove ice bath and allow to warm to room temp
Position flask in hot water bath, light bunsen and maintain water bath for 20mins
Allow apparatus to cool
Distil product

Question 3

CPAC 6: Investigating chlorination if 2-methylpropan-2-ol (produce and purify sample of 2-chloro2-methylpropane)
Method

Answer 3

Pour 10cm3 oh alcohol (2methylpropan2ol) and 35cm3 of concentrated HCl into a large conical flask & swirl contents gently
Place & remove bung from time to time and continue swirling for ~20 mins. Should be 2 layers
Add 6g of powdered anhydrous calcium chloride to flask and swirl until dissolved
Transfer mixture to separating funnel. Separate (describe how) retaining the upper organic layer in the funnel
Repeat washing with 20cm3 of sodium hydrogencarbonate. Discard lower layer x2
Run off organic layer into small conical flask. Add a spatula of anhydrous sodium sulfate. Swirl with bung until clear
Decant into 50cm3 pear shaped flask and set up for distillation
Collect fraction between 50-52 degrees