Use the References to seeess important valees if aeeded for this question. Write

Question

Use the References to seeess important valees if aeeded for this question. Write the cell notation for an electrochermical cell consisting of an anode where Zn () is oxidized to Zn1 (aq) and a cathode where Cr (aq) is reduced to Cr+ (ag) at a platinum electrode. Assume all aqueous solutions have a concentration of 1 moVL and gases have a pressure of bar. Zn(s)Zn2+(aq, 1 M)IC (aq, 1 M) C2 (aq, 1 M)Pt(s) An error has been detected in your answer. Check for typos miscalculations etc. before submitting your answer Submit Answer Try Another Version 1 item attempt remaining

Explanation / Answer

Remember that each species will have a specific reduction potential. Remember that this is, as the name implies, a potential to reduce. We use it to compare it (numerical) with other species.

Note that the basis if 2H+ + 2e- -> H2(g) reduction. Therefore E° = 0 V

All other samples are based on this reference.

Find the Reduction Potential of each reaction (Tables)

Zn2+(aq) + 2e– Zn(s) –0.76;

Cr3+(aq) + e– Cr2+(aq) –0.407

The most positive has more potential to reduce, it will be reduced

The most negative will be oxidized, since it will donate it selectrons

For total E°cell potential:

E°cell = Ered – Eox

E°cell = Ecr - Ezn = -0.407 - -0.76 = 0.353 V

E°cell = 0.353 V

Cell notation:

left side:

oxidation

Pt(s)/ Zn(s) / Zn2+(aq) // Cr3+(aq,1M) / Cr2+(aq, 1M)

note that Pt electrode must go on the oxidation side

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