## Relationship between pH, protanation and molarity

Silvino Jimenez 1A
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

### Relationship between pH, protanation and molarity

Hi

How can pH or pOH be found
given % protonation/deprotanation and molarity?

Ty!

Katie Lam 1B
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

### Re: Relationship between pH, protanation and molarity

You use the molarity of H30+ and OH- to find the pH and pOH by taking the -log of each.
-log[H30+]=pH
-log[OH-]=pOH

Rachel Formaker 1E
Posts: 86
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 2 times

### Re: Relationship between pH, protanation and molarity

For an acid, when given the initial molarity and percent deprotonation, you multiply the initial molarity by the percent deprotonation (as a decimal, so over 100) to find the concentration of H3O+ ions in solution.
You then use this concentration to find pH in the normal way (pH=-log[H3O+])

For bases, you do the same thing except for OH- ions and pOH

Eruchi Okpara 2E
Posts: 53
Joined: Fri Sep 28, 2018 12:28 am

### Re: Relationship between pH, protanation and molarity

When solving for the percent deprotonation, is it always going to be the value you got for X (from the ICE table) divided by the initial concentration given?

Eruchi Okpara 2E
Posts: 53
Joined: Fri Sep 28, 2018 12:28 am

### Re: Relationship between pH, protanation and molarity

Can deprotonation still be found if we are given initial concentrations for both the reactants and products?

Max Hayama 4K
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

### Re: Relationship between pH, protanation and molarity

Yes! All you need to do is divide the equilibrium concentration of the conjugate acid/base by the initial concentration of the corresponding acid and base.

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