## pH and cell potential

$E_{cell} = E_{cell}^{\circ}-\frac{RT}{nF}\ln Q$

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### pH and cell potential

Hi, why and how does increasing the pH of a solution increase the cell potential of a battery? Thanks.

Chem_Mod
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### Re: pH and cell potential

Increasing the pH of a solution DOES NOT always increase the cell potential of a battery. You need to consider the Nernst's equation $E_{cell}=E^{\circ}-\frac{0.0592V}{n}\log Q$
. If a pH change in the cell result in a change in Q, then it will affect Ecell.

604596531 2k
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### Re: pH and cell potential

like in the case of question 3 on the 2011 practice final i was wondering why the cell potential would increase if the pH increased since doesn't that make the pOH smaller and making the concentration of the OH smaller and making bigger Q and making it more -

Jocelyn
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### Re: pH and cell potential

So since the pH increases the pOH decreases and the CONCENTRATION of OH- increases therefore making Q smaller so E is then increasing.

Rachael_1H
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### Re: pH and cell potential

Why would the pOH decreasing cause the OH- concentration to increase? Wouldnt it decrease according to the equation pOH=-log[OH-]?

KaylaH
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### Re: pH and cell potential

Rachael Ronzano 1H wrote:Why would the pOH decreasing cause the OH- concentration to increase? Wouldnt it decrease according to the equation pOH=-log[OH-]?

Because if pH is increased from 11 to 13 (just for example), that means that pOH would decrease to 1. This means [OH-]=10^-1. If you plug this new value in for the concentration of OH- and solve for E, you will get a greater cell potential.

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