## Intermediates in pre equilibrium

$K = \frac{k_{forward}}{k_{reverse}}$

Armo_Derbarsegian_3K
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Joined: Sat Jul 09, 2016 3:00 am

### Intermediates in pre equilibrium

When you replace the intermediate in the rate law when doing pre equ problems, what do you do if you end up with another intermediate in your answer?

ClO-+H2O<->HClO+OH- fast
HClO+I-<->HIO+Cl- slow
HIO+OH-<->IO-+H2O fast

so the rate would be k2[HClO][I-] but HClO is an intermediate;

K=[OH-][HClO]/[ClO-]=k1/k'1 omit H2O b/c assumed liquid?
solve for [HClO]= k1[ClO-]/k'1[OH-]
k2*k1[ClO-]/k'1[OH-])[I-]
and that is what the solution is, is it okay to have [OH-], a "secondary" intermediate, in the rate?

Chem_Mod
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### Re: Intermediates in pre equilibrium

Water/aqueous solution has H2O, H+, -OH. They are not intermediates as they are all the time present in water, and therefore can be present in rate laws if involved in the slow step of a reaction.

Some reactions are referred to as acid catalyzed and H+ is present in the rate law. Meaning the more acidic the solution the faster the reaction.

Shark
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### Re: Intermediates in pre equilibrium

lilyjustine_1G
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Joined: Fri Jun 17, 2016 11:28 am

### Re: Intermediates in pre equilibrium

Yes this sounds like problem 15.101

Suk Jin Song 3L
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### Re: Intermediates in pre equilibrium

Ohhh, so the review session will also go over post-midterm materials? That's also good to hear. I had a few questions regarding chemical kinetics after Quiz 2.

Manvita_Mareboina_3K
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### Re: Intermediates in pre equilibrium

I think the review session today is limited to the midterm and questions within that. But Do you know if there will be any review of the new organic material?

sas_budge_1l
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### Re: Intermediates in pre equilibrium

If there is 2 transition states with 2 steps involved in a reaction, can there only be 1 intermediate or is it possible to have 2 intermediates?

Julie Barreto 3A
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### Re: Intermediates in pre equilibrium

there can be 2 transition states in an electorphillic reaction

Julie Barreto 3A
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### Re: Intermediates in pre equilibrium

usually there is one intermediate

Eric_pierce_3E
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### Re: Intermediates in pre equilibrium

This was very helpful thank you