To what pH should you adjust a standard hydrogen electrode to get an electrode potential of -0.128 V ? (Assume that the partial

Question

2 years ago

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pressure of hydrogen gas remains at 1 atm.) Express your answer using two decimal places.\

1 answer:

8090 [49] · Answer 1 · 2022-11-09T15:31:30+03:00

The pH of the standard hydrogen electrode that has electrode potential of -0.128 V is 4.3.

The equation of the hydrogen electrode is;

2H^+(aq) + 2e ⇄ H2(g)

The standard electrode potential of hydrogen is 0.00 V

Using the Nernst equation;

Ecell = E°cell - 0.0592/n log Q

Now;

E°cell = 0.00 V

n = 2

Q = 1/[H^+]

-0.128 = 0.00 - 0.0592/2 log 1/[H^+]

-0.128 = 0.00 - 0.0296 log 1/[H^+]

-0.128 = - 0.0296 log 1/[H^+]

-0.128/ - 0.0296 = log 1/[H^+]

1/[H^+] = Antilog (4.32)

[H^+] = 4.79 × 10^-5

Now;

pH = -log[H^+]

pH = -log (4.79 × 10^-5)

pH = 4.3