# Thread: Logarithmic scale for pH: how many times more acid is pH 5.2 than pH 6.5?

1. ## Logarithmic scale for pH: how many times more acid is pH 5.2 than pH 6.5?

Hi, my question is about the logarithmic scale used for pH.
I know pH 5 is 10 times more acid than pH 6 and 100 times more acid than pH 7.
What about fractions of pH values?
Is pH 4.5 actually 50 times more acid than ph 6?
I need to know...how many times more acid is pH 5.2 than pH 6.5?
I would really appreciate any help on this.
Thank you.

2. Check out this short example, and let us know if you have any more questions.

3. ## Logarithmic scale for pH 2

Originally Posted by mmm4444bot
Check out this short example, and let us know if you have any more questions.
Hi, thank you so much for the reply.
The equation makes sense. When I do the example I get the same answer. Also when I use whole integers I get the correct answer (pH5 is 10 times more acid than ph6) but when I tried my numbers comparing pH 5.2 and 6.5, it doesn't seem to work.
See below:
10-5.2 = 6.31 x 10-6
10-6.5 = 3.16 x 10-7 = 31.6 x 10-6

6.31/31.6 = 0.1997

I don't know what I'm doing wrong (feeling kind of stupid). pH 5.2 should be about 50 times more acid than 6.5 right (pH5 is 100 x more acid than pH7)??

4. Originally Posted by tambaqui
10-5.2 = 6.31 x 10-6
10-6.5 = 3.16 x 10-7 = 31.6 x 10-6
3.16 * 10^(-7) = 0.000000316

31.6 * 10^(-6) = 0.00000316

They're not equal. Did you perhaps mean to convert as follows?

6.31 * 10^(-6) = 63.1 * 10^(-7)

5. ## Logarithmic scale for pH: how many times more acid is pH 5.2 than 6.5? answer: 19.97

Originally Posted by stapel
3.16 * 10^(-7) = 0.000000316

31.6 * 10^(-6) = 0.00000316

They're not equal. Did you perhaps mean to convert as follows?

6.31 * 10^(-6) = 63.1 * 10^(-7)

thank you, I got 19.97 for an answer.

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