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Kristine Marie M.

How do you calculate H3O+ from molarity?

Alec Smith  Follow

As a quora user who asks how many inches in a foot, you’re in WAY.over your head with this question!

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Allistar Evans  Follow

If you are referring to a question dealing with the dissociation of an acid, the answer depends on the identity of the acid.

Strong acid dissociate completely in aqueous solution. Hydrochloric acid is an example, The value of [H^+] in 0.10 M HCl is 0.10 M.

Weak acids do not dissociate completely. Finding the value of [H^+] requires knowing the value of Ka for the acid and the initial concentration of the solution.

Consider 0.10 M acetic acid, CH3COOH.

Ka = 1.8E-5 = [H^+][CH3COO^-]/[CH3COOH]

1.8E-5 = (y)(y)/0.10-y)

This is solved quickly by assuming y<<0.10.

That gives y = 0.0013 (Assumption valid!)

“E” represents “x10^”

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