Required practical 5 :Distillation of a product from a reaction.

Question 1

Apparatus for distillation

Answer 1

-Round-bottom flask
-condenser (horizontal) -water in at the bottom and out at the top
-Heat source (Bunsen)
-Thermometer
Collection vessel - in ice water bath
- anti-bumping granules

Question 2

What is the role of the anti bumping granules in this experiment?

Answer 2

Stops the mixture boiling too vigorously by preventing the formation of large bubbles.

Question 3

Write an balanced symbol equation for the reaction that has occurred between ethanol and the limiting acidified potassium dichromate - use [O] to represent your oxidising agent.

Answer 3

CH3CH2OH + [O] → CH3CHO + H2O

Question 4

If we had used excess potassium dichromate and reflux what organic product would we have obtained? Write an equation to represent this.

carboxylic acid

Answer 4

CH3CH2OH + 2[O] → CH3COOH + H2O

Question 5

What is the Tollens solution acting as?
What is the organic production in the Tollens test?

Answer 5

• Tollens = oxidising agent
• organic product = ethanoic acid

Question 6

Testing for Ethanal

Answer 6

(Making Tollen’s Reagent)

1) Add 5 drops of NaOH (aq) to 2 cm3 of AgNO3 solution.

2) Add just enough dilute NH3 to dissolve the brown precipitate and warm gently in the water baths.

(Actual Test)

3) To 5 cm3 of warm Tollens’ reagent add 10 drops of the ‘ethanal’ and wait a few minutes.

4) silver mirror forms = ethanal present