IGCSE electrolysis question

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Darwinion
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One of the well known reactions in GCSE is the electrolysis of molten lead bromide. This results in bromine gas given at the anode and molten lead produced at the cathode.

I'm doing my revision now and working on the prediction of substances before electrolysis. More than one source has told me that if the metal is above hydrogen in the reactivity series then hydrogen gas is produced. In order for the metal itself to be produced it must be below hydrogen in the reactivity series.

BBC Bitesize is one source of this information:
http://www.bbc.co.uk/schools/gcsebit...ysisrev4.shtml

You've guessed it... the electrolysis of lead bromide does not follow this information.
Why is this please? What do I need to be looking for? I is confuzzled.
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Dillan2201
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It is because molten lead bromide is an ionic compound which contains only two ions Pb2+ and Br-.

The other electrolysis is 'electrolysis of aqueous solutions' which has the two ions from the ionic compound but also has hydrogen ions (H+) and hydroxide ions (OH-). So then it is the least reactive substance at each anode or cathode that is given off
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Darwinion
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(Original post by Dillan2201)
It is because molten lead bromide is an ionic compound which contains only two ions Pb2+ and Br-.

The other electrolysis is 'electrolysis of aqueous solutions' which has the two ions from the ionic compound but also has hydrogen ions (H+) and hydroxide ions (OH-). So then it is the least reactive substance at each anode or cathode that is given off

You know... I was just thinking about this and realised the very basic schoolboy error I was making But thank you anyway for your quick response!

I need to look at questions more clearly in exams to stop these silly mistakes.
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Dillan2201
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(Original post by Darwinion)
You know... I was just thinking about this and realised the very basic schoolboy error I was making But thank you anyway for your quick response!

I need to look at questions more clearly in exams to stop these silly mistakes.
Yeah I get you, especially in Chemistry you need to think through basically every question quite carefully before you answer. Good luck in the exam
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