Homework Question

$\Delta G^{\circ} = -nFE_{cell}^{\circ}$

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Homework Question

What range in volts does a voltmeter need to have to measure pH in the range of 1 to 14 at 25 Celsius if the voltage is zero when pH is 7?

I understand everything for the most part, but can anyone explain to me why we have to do this:

.025693ln(0.1/1x10^-13)= 0.710V
.025693ln(1x10^-14/1.0)=-0.828V

Why is do we have those values for lnK? Why specifically 1x10^-13 and 1.0?

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Re: Homework Question

1 x 10–13 is the concentration of OH(aq) at a pH of 1, and 1.0 is [OH] at pH 14.

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Re: Homework Question

On closer inspection, this appears to be a mistake. Use $E_{cell} = E_{cell}' + \frac{RT}{F} ln [H^+]$