Practicals

Question 1

Titration 5marks

Answer 1

Remove fixed amount of one solution using a pipette into a conical flask and fill up the burette with the other solution
Add indicator and state colour change
Add solution from burette to conical flask until indicator changes colour
Technique mark: rinsing burette/ pipette, white tile, swirling, adding slowly
Repeat titrations until concordat results obtained

Question 2

Why do you release the bung periodically in chlorination of (CH3)3CCl

Answer 2

To release pressure as H2O(g) produced

Question 3

Why do you add CaCl2 (s) to the flask of two layers in chlorination of (CH3)3CCl

Answer 3

Dehydration agent: removes H2O(l) from upper and lower layers to purify them

Question 4

Why do you add NaHCO3 to the haloalkane layer in chlorination of (CH3)3CCl

Answer 4

Removes excess HCl, producing CO2 and H2O