Question

Is the electrochemical cell spontaneous or not spontaneous as written at 25 ∘C ? spontaneous not spontaneous Calculate the potential of the electrochemical cell and determine if it is spontaneous as written at 25 ∘C . Pt(s) || Sn2+(0.0023 M),Sn4+(0.13 M) ‖‖ Fe3+(0.11 M),Fe2+(0.0037 M) || Pt(s) ????∘Sn4+/Sn2+=0.154 V????∘Fe3+/Fe2+=0.771 V

Answer 1

Answer:

The cell potential is 0.609 V. Given E > 0 the electrochemical cell is spontaneous as written.

Explanation:

Let's consider the oxidation and reduction half-reactions and the global reaction.

Anode (oxidation): Sn²⁺(0.0023 M) ⇒ Sn⁴⁺(0.13 M) + 2 e⁻

Cathode (reduction): 2 Fe³⁺(0.11 M) + 2 e⁻ ⇒ 2 Fe²⁺(0.0037 M)

Global reaction: Sn²⁺(0.0023 M) + 2 Fe³⁺(0.11 M) ⇒ Sn⁴⁺(0.13 M) + 2 Fe²⁺(0.0037 M)

The standard cell potential (E°) is the difference between the standard reduction potential of the cathode and the standard reduction potential of the anode.

E° = E°red,cat - E°red,an

E° = 0.771 V - 0.154 V = 0.617 V

The Nernst equation allows us to calculate the cell potential (E) under the given conditions.

$E=E\° -\frac{0.05916}{n} logQ\\E=E\° -\frac{0.05916}{n} log\frac{[Sn^{+4}].[Fe^{2+}]}{[Sn^{2+}].[Fe^{3+} ]} \\E=0.617V-\frac{0.05916}{2} log\frac{(0.13).(0.0037)}{(0.0023).(0.11)} \\E=0.609V$

The cell potential is 0.609 V. Given E > 0 the electrochemical cell is spontaneous as written.