## pH and pOH

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kanikubari
Posts: 30
Joined: Fri Dec 07, 2018 12:18 am

### pH and pOH

How do you know which one to solve for? For instance on 6B.5.

annabel 2A
Posts: 67
Joined: Fri Sep 28, 2018 12:18 am

### Re: pH and pOH

What does the problem say? I think generally it tells you which to solve for.

Esther Lee 4H
Posts: 67
Joined: Fri Sep 28, 2018 12:29 am

### Re: pH and pOH

dont know what the question says but I think for most questions it specifies to solve for either one or the other or both

Kavvya Gupta 1H
Posts: 35
Joined: Fri Sep 28, 2018 12:21 am

### Re: pH and pOH

I don't know what the problem says but usually, it will tell you what to solve for in the problem. Given the reaction, you will know what you have to solve for. For instance if it NH3 + H20 -> NH4+ + OH- you would solve for Kb and pOH and if it was HCl + H20 -> Cl- + H30+.

Tessa Lawler 1A
Posts: 57
Joined: Fri Sep 28, 2018 12:18 am

### Re: pH and pOH

If it doesn't tell you explicitly, just go off of what's present in the equation. Which do you end up with in the products - H3O+ or OH-? If it's OH-, then pOH. If it's H3O+, then pH. And of course you can always calculate one once you have the other using the equation pH + pOH = 14.

Luis_Yepez_1F
Posts: 50
Joined: Fri Sep 28, 2018 12:18 am

### Re: pH and pOH

Usually the question will ask you to solve for one or the other.

505211599
Posts: 60
Joined: Fri Sep 28, 2018 12:28 am

### Re: pH and pOH

The question will tell whether to solve for ph or pOH.

Casandra
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

### Re: pH and pOH

The question will ask you to solve for pH or pOH, and the problem will also give you sufficient information to be able to solve for this.

Kaylee Kang 1G
Posts: 65
Joined: Fri Sep 28, 2018 12:24 am

### Re: pH and pOH

The probable will typically tell you whether to solve for pH or pOH.

Lauren Huang 1H
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Re: pH and pOH

Also, when your chemical reaction includes H30+, you are finding the pH, and when it includes OH-, you are finding the pOH. Make sure to use the equation pH+pOH=14 if you are trying to convert between the two.

Mona El Masri 1F
Posts: 34
Joined: Fri Sep 28, 2018 12:20 am

### Re: pH and pOH

pOH- base
pH-acid

then you can use the pOH+pH=14 to solve for the other one

Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: pH and pOH

The question will tell you which to solve for.

905084274
Posts: 42
Joined: Fri Sep 28, 2018 12:22 am

### Re: pH and pOH

Typically if you are given a base, you solve for pOH, but if you are asked to find the pH, then you must convert from pOH to pH by using this formula: -14.00 = pOH + pH. Or 14.00 - pOH = pH

MichelleRamirez_2F
Posts: 63
Joined: Fri Sep 28, 2018 12:28 am

### Re: pH and pOH

Usually the problem you are solving will tell you which one to solve for. In some occasions you may have to solve for both for the same problem.

Anna O 2C
Posts: 98
Joined: Fri Sep 28, 2018 12:19 am

### Re: pH and pOH

Often times if they don't say it outright, you can infer through whether they are referring to the concentrations of acids or bases in a solution.

Nicolle Fernandez 1E
Posts: 56
Joined: Fri Sep 28, 2018 12:25 am
Been upvoted: 1 time

### Re: pH and pOH

If it doesn’t say specifically look at the products as OH would be pOh and H3O would be pH, sometimes it will tell you specifically

Posts: 91
Joined: Fri Sep 28, 2018 12:16 am

### Re: pH and pOH

It is always best to go with what is given, if OH is formed, then solve for pOH and then 14-pOH to find pH. If H+ is a product of the disassociation, then solve for pH and then use 14-pH if they are asking for pOH?

Ashe Chen 2C
Posts: 31
Joined: Mon Jan 07, 2019 8:23 am

### Re: pH and pOH

The problem should specify, but if not it is usually safe to assume you should calculate for what is given, ie if the reaction forms H+ ions you should solve for pH and if OH- ions are formed solve for pOH.

jocelyntzeng
Posts: 59
Joined: Fri Sep 28, 2018 12:18 am

### Re: pH and pOH

it will ask you specifically but usually it is pH