Test 2 #5

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Michelle Song 1G
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Joined: Wed Nov 14, 2018 12:23 am

Test 2 #5

Postby Michelle Song 1G » Tue Mar 12, 2019 4:34 pm

Once you get K2 do you
1. take the square root of it to find [H3O+] and assume that [H3O+] = [OH-] and get the pH from there

2. put 10^-7 as [H3O+] because the pH is 7 and divide K2 by that to get [OH-] and see which one is higher to decide if it's acidic or basic?

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Joined: Thu Nov 08, 2018 12:17 am

Re: Test 2 #5

Postby PranitKumaran1F » Tue Mar 12, 2019 4:43 pm

You do the second way. You can't assume that [H30]=[OH] in a pH = 7 solution because that only applies when K = 10^-14. Since K2 will be a different value, you have to solve for [OH] by dividing K2 by [H30] in a pH=7 solution. If [H30]>[OH] then the solution is acidic at pH = 7 and vise versa.

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