Chemistry core practical 6

Question 1

Aim

Answer 1

To produce a pure sample of 2-chloro- 2-methylpropane in halogenation

Question 2

Preparing the reaction mixture

Answer 2

Pour 10cm3 of 2-methylpropan-2-ol + 35cm3 of concentrated HCl into a large conical flask with a bung and slowly swirl + release pressure for 20 mins

Question 3

After swirling the reaction mixture, what does it look like?

Answer 3

Produce 2 layers: organic layer (top) and aqueous layer (bottom)

Question 4

Removing impurities of water in the organic layer

Answer 4

Add 6g of anhydrous calcium chloride to flask

Question 5

Why add anhydrous calcium chloride?

Answer 5

So any unreacted aqueous water in organic layer (impurities) settles in the bottom aqueous layer

Question 6

Using a separating funnel

Answer 6

Transfer 2 layers of mixture into a separating flask and leave to settle
Run off and discard lower aqueous level

Question 7

Removing unreacted HCl

Answer 7

Add 20cm3 of sodium hydrogen carbonate into separating funnel
And swirl + take off bung to release pressure caused by release or CO2
Run off and discard the lower aqueous level

Question 8

Collecting the organic layer

Answer 8

Run off organic layer into a small conical flask from the separating funnel

Question 9

Step 10

Answer 9

Add anhydrous sodium sulfate to the small conical flask and place bung, leave until fully clear + occasionally swirl

Question 10

Step 11

Answer 10

Pour organic liquid into pear shaped flask + distillation at 50°c

Question 11

Why add sodium hydrogen carbonate?

Answer 11

To remove unreacted HCl