RP5- Distillation

Question 1

(alternative a)

Potassium manganate (VII) is oxidising and harmful.
Sodium ethanedioate is toxic.
Suggest safety precautions, other than eye protection, that should be taken when:
* filling the burette with potassium managate (VII) solution
* dissolving solid sodium ethanedioate in water

(2)

Answer 1

• fill burette at eye level
• wear gloves (toxic)

Question 2

State the colour change seen at the end point of a titration between sodium ethanedioate and potassium manganate (VII). (1)

Answer 2

colourless –> pink
(colourless in acid, pink in alkali)

same as phenolpthalein- opp to what we expect

Question 3

Give two practical steps needed before recording initial burette reading. (2)

Answer 3

1. remove funnel
2. ensure jet is filled/ x air bubbles (open tap to fill space below tap)