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Topic: pH vs Temperature  (Read 3206 times)

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Offline yasas.w

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pH vs Temperature
« on: December 25, 2013, 09:20:36 AM »
Lets say there's an HCl solution in 30°C and its pH=2
If the same solution is kept in an environment of 25°C what happenes to the pH value?

Offline billnotgatez

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Re: pH vs Temperature
« Reply #1 on: December 25, 2013, 11:14:39 AM »
There are lots of places on the internet that discuss this
here is one of them
http://www.chembuddy.com/?left=pH-calculation&right=water-ion-product
It has a table showing  pH variation with temperature where pH of 7 is 25C

Also you should discuss your work on the question - not just ask a question
Please read forum rules

Offline yasas.w

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Re: pH vs Temperature
« Reply #2 on: December 25, 2013, 11:20:54 AM »
There are lots of places on the internet that discuss this
here is one of them
http://www.chembuddy.com/?left=pH-calculation&right=water-ion-product
It has a table showing pH with temperature

its about the neutral temperature which means it doesn't solve my question  ;D

Offline billnotgatez

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Re: pH vs Temperature
« Reply #3 on: December 25, 2013, 11:32:36 AM »
I am sorry but I modified my post after you answered my post
But if you read the text in the link it says
Quote
In a real world Kw value is highly temperature dependent

You can also look at WIKI
http://en.wikipedia.org/wiki/PH
for discussions on calculations

And as yet we have not seen your work on this question
Have you read the forum rules?

Offline yasas.w

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Re: pH vs Temperature
« Reply #4 on: December 25, 2013, 12:31:13 PM »
I am sorry but I modified my post after you answered my post
But if you read the text in the link it says
Quote
In a real world Kw value is highly temperature dependent

You can also look at WIKI
http://en.wikipedia.org/wiki/PH
for discussions on calculations

And as yet we have not seen your work on this question
Have you read the forum rules?

sorry I just read them =)
Well the original question is(I'm translating it into English forgive me if there are any mistakes)
"In a HCl solution pH=2, temperature is 30°C.
What is the pOH value if you keep the same solution in an environment of 25°
(In 25°C pKw=14)"

And I thought that pH doesn't depend on the temperature and I thought that the answer should be 12  :)

Well I know what happens to Kw with the variations of the temperature but I was wondering whether the temperature really affects the pH value of the HCl solution.

Offline Borek

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Re: pH vs Temperature
« Reply #5 on: December 25, 2013, 04:19:34 PM »
Changes in pH value are most likely neglectable.

Doesn't mean they don't exist, but they are quite difficult to describe, as there are several competing phenomena present.
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