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Question about Photolysis

Hi guys, I covered the topic of photolysis today and I ran into something I do not understand.
The new bio spec textbook says (pg 271, right at the top) that photolysis of water produces H+ ions (Protons) and OH- ions. It then says (on pg 272 near the bottom, under the title photolysis of water) that the photolysis of water produces H+ (protons), e- (electrons) and Oxygen.

I understand how both routes would work but I do not understand, when photolysis produces the H+ and OH- ions and when it produces the protons, electrons and Oxygen and when do we mention which products?
Original post by LightAtTheEnd
Hi guys, I covered the topic of photolysis today and I ran into something I do not understand.
The new bio spec textbook says (pg 271, right at the top) that photolysis of water produces H+ ions (Protons) and OH- ions. It then says (on pg 272 near the bottom, under the title photolysis of water) that the photolysis of water produces H+ (protons), e- (electrons) and Oxygen.

I understand how both routes would work but I do not understand, when photolysis produces the H+ and OH- ions and when it produces the protons, electrons and Oxygen and when do we mention which products?

both are correct. it is very important to understand the chemistry behind it, so it's good to ask.

I will go through it:

by photolysis: 4H2O ---> 4H+ + 4OH-

OH- is unstable so:

4 OH- --> 4 (OH) + 4 e -
4(OH) --> 2H2O + O2

So being unstable, will react with other OH available to form water and oxygen.

Hope this helps
(edited 7 years ago)
Original post by Daniel Atieh
both are correct. it is very important to understand the chemistry behind it, so it's good to ask.

I will go through it:

by photolysis: 4H2O ---> 4H+ + 4OH-

OH- is unstable so:

4 OH- --> 4 (OH) + 4 e -
4(OH) --> 2H2O + O2

So being unstable, will react with other OH available to form water and oxygen.

Hope this helps


Thank you so much! I had asked one of my biology teachers and he had claimed that it ha something to do with the chemistry behind it.
Original post by LightAtTheEnd
Thank you so much! I had asked one of my biology teachers and he had claimed that it ha something to do with the chemistry behind it.


no problem at all.

If I may ask, which board you do?
(edited 7 years ago)
Original post by Daniel Atieh
no problem at all.

If I may ask, which board you do?


The new AQA spec for all sciences
Original post by LightAtTheEnd
The new AQA spec for all sciences


I believe this is only available in the UK?

Anyway, I did edexcel, so I suggest you to pass over some papers for further practice. Their questions are actually good.

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