pH/concentration

[yellowjellybean]

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"The concentration of H3CCO2H between the two points in question differ by a factor of 2. This means that the pH of the two solutions differs by -log sqrt(2)..."

Can someone please explain how they got -logsqrt (2) when the concentration is doubled? Thanks.

 

[Bomikepa]

i thought you could only use the - log [H+] for when its a strong acid?

 

[yellowjellybean]

Yeah I don't know, the quoted text is from TBR from one of the titration passages

 

[mehc012]

"The concentration of H3CCO2H between the two points in question differ by a factor of 2. This means that the pH of the two solutions differs by -log sqrt(2)..."

Can someone please explain how they got -logsqrt (2) when the concentration is doubled? Thanks.

Henderson Hasselbalch?
Honestly, though, if you want a thorough explanation, it would help to post the entire question. My guess is that you're neglecting the pKa value somehow...this isn't a strong acid, you can't assume that [H+] doubles just because [HA] did.