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A-Level Chemistry - Oxidation of Ethanol

Hi,

I was looking over the method which Edexcel A-Level provides for Core Practical 5 (the oxidation of ethanol). I missed this one in school so I am now having to catch up on it.

I will attach it below but I had a few questions and I would be really grateful for anyone's help.

1. When acidified sodium dichromate is added to the pear-shaped flask (by itself), why does it need to be cooled in an ice-water bath.

2. Why is it so important to add ethanol *slowly/drop by drop* through the reflux condensor, whilst being *cooled by water bath*.

3. When it is refluxed, why is a hot water bath with a bunsen burner used rather than just a bunsen burner by itself?
Reply 1
Original post by joycem12
Hi,
I was looking over the method which Edexcel A-Level provides for Core Practical 5 (the oxidation of ethanol). I missed this one in school so I am now having to catch up on it.
I will attach it below but I had a few questions and I would be really grateful for anyone's help.
1. When acidified sodium dichromate is added to the pear-shaped flask (by itself), why does it need to be cooled in an ice-water bath.
2. Why is it so important to add ethanol *slowly/drop by drop* through the reflux condensor, whilst being *cooled by water bath*.
3. When it is refluxed, why is a hot water bath with a bunsen burner used rather than just a bunsen burner by itself?

1.

The reaction is very exothermic. If allowed to "run away" it can explode. There is an orange stain on the chemistry lab ceiling for this very reason.

2.

Same

3.

Better temperature control. The Bunsen focusses the flame at one point. Water spreads the heat out.

Reply 3
Thank you!

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