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Postby sarahtang4B » Mon Jan 21, 2019 11:36 am

On 6B9 on the homework 7th edition I get a negative pH for 0.176 after doing -log[H3O+], do we just convert it to negative or am I doing something wrong with calculating?

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Re: homework

Postby aisteles1G » Mon Jan 21, 2019 2:02 pm

I got this too and I think it might just be an error? It wouldn't make sense for it to be a negative value but going by the formulas and exact calculations that's what it turns up as on my calculator as well :/ I think maybe just a mistake

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Re: homework

Postby Chem_Mod » Mon Jan 21, 2019 2:07 pm

You should be getting a negative number for pH, this is an extremely strong acid since the concentration of H3O+ is on an order of magnitude that is greater than 10-1. This is when an acid will not follow the normal pH scale, where the pH is between 0 and 14, instead when you have whats called a "super acid" like here the pH is <0 or if you have a "super base" the pH can be >14. The answer in the book is incorrect or it is trying to correct it and keep it on the normal pH scale.

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