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## Homework Statement

2.00M chlorus acid and 2.00M formic acid are mixed. What is the pH?

## Homework Equations

Ka of chlorus acid is 1.1×10

^{-2}

Ka of formic acid is 1.78×10

^{-4}

## The Attempt at a Solution

For chlorus acid with quadratic equation to find x:

x²+0.011x-0.022

(-0.011[tex]\pm[/tex][tex]\sqrt{}0.000121-4(1)(-0.022)[/tex])/2

(-0.011[tex]\pm[/tex]0.297)/2

The positive number of the two choices is 0.143

For formic acid, and the x being small enough to neglect, x is:

x²/2=0.000178

x²=0.000356

x=0.0189

When mixing weak acids, I think I was told that only the acid with the larger Ka value matters, meaning taking the negative log of chlorus acid's H ion gets -log0.143=0.845.

I wasn't sure this was correct so then I tried adding the two H ion concentration from each acid to find their pH. I did 0.143+0.0189=0.162 and negative log that for 0.791.

I'm not sure it is added this way, since I got a bit confused about the idea of adding molarity together, so I divided by 2 first then negative log for 1.09.

Still I'm not sure this is correct so I think I took the wrong steps. How is this correctly done?