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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: xoedusk on March 21, 2007, 05:04:58 AM

Title: Mixing pH, anyone?
Post by: xoedusk on March 21, 2007, 05:04:58 AM

Good evening,

I'm trying to come up with an equation that describes the mixing of two solutions of different pHs. More specifically, I'm trying to find out the resulting pH.

Say, for example, if we mix x liters of solution A that has a pH of "a" into y liters of solution B that has a pH of "b", what would the resulting pH be?

In my application (fish tanks), the pH usually stays between 5 and 8.

My initial reaction is just to approximate the hydrogen ion concentrations by -Log(pH). Then it is a normal mixing concentration problem. But I'm wondering if this is correct, or if there is something I am missing?

If my thinking is correct, mixing half pH 7 water with half pH 6 water creates 6.26 pH?

Title: Re: Mixing pH, anyone?
Post by: xiankai on March 21, 2007, 06:23:45 AM

that's right.

Title: Re: Mixing pH, anyone?
Post by: xoedusk on March 21, 2007, 07:21:07 AM

Thank you xiankai.