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Which half-cell, when connected with the Cu2+ /Cu half-cell (Cu2+ + 2e- → Cu), will result in a positive cell potential? 1-/12 Fe2+/Fe3+

Ag/Ag Sn2+ /Sn

User Jschrab
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1 Answer

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Okay, let's evaluate the options to determine which half-cell will result in a positive cell potential when combined with the Cu2+/Cu half-cell:

1. Fe2+/Fe3+: This half-cell converts Fe2+ ions to Fe3+ ions. The standard cell potential for Fe2+/Fe3+ is +0.77 V. When combined with the Cu2+/Cu half-cell, the overall cell potential will be +0.77 V - E°Cu2+/Cu = +0.77 V - 0.34 V = +0.43 V. This is a positive value, so Fe2+/Fe3+ will work.

2. Ag/Ag+: The standard cell potential for Ag/Ag+ is +0.80 V. Combined with Cu2+/Cu, the cell potential would be +0.80 V - 0.34 V = +0.46 V. This is also positive, so Ag/Ag+ can be used.

3. Sn2+/Sn: The standard cell potential for Sn2+/Sn is -0.14 V. Combined with Cu2+/Cu, the cell potential would be -0.14 V - 0.34 V = -0.48 V. This is negative, so Sn2+/Sn will not result in a positive cell potential.

In summary, the half-cells that will work with Cu2+/Cu to give a positive overall cell potential are:

1. Fe2+/Fe3+

2. Ag/Ag+

Sn2+/Sn will give a negative potential and cannot be used.

Does this make sense? Let me know if you have any other questions!

User Mfnx
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