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Hello, I've been struggling with this exercise because I don't know which pH result is correct.

 

I was given:

Calculate pH

pKa = 10.25

[HCO-3] = 25.2 mmol/L --> 2.52 x10-3

[CO3-2] = 32.0 umol/L --> 3.2 x10-5

 

So, pH = pKa + log ([A-]/[HA])

 

The correct answer should be (the answer in the book): pH = 7.4

 

But I keep getting: pH = 13.1, what am I doing wrong?

 Jun 19, 2020
 #1
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Surprise! Your calculation is what Wolfram/Alpha also gets. Go to this link and enter your formulas in there and see what you get. I don't know much about chemistry.

 

https://www.wolframalpha.com/input/?i=Calculate+pH++pKa+%3D+10.25%2C++25.2+mmol%2FL%2C++32.0+umol%2FL+

 Jun 19, 2020

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