Question

The standard cell potential for : 3A(s) + B+3(aq) → 3A+(aq) + B(s) is E° = 2.00 V. How does Ecell compare to Eo when [A+] = 0.50, [B3+] = 1.5 x 10-3 at 298 K.

Answer 1

E cell = 1.962 V

Further explanation

Given

E° cell = 2.00 V

Required

E cell at 298 K

Solution

The potential cell for nonstandard conditions we can use the Nernst equation

`\rm E = E ^ o -\frac {RT} {nF} lnQ`

For temperature T = 298 K,

`\rm E = E ^ o -\frac {0.0592V} {n} log \: Q`

Reaction

3A(s) + B+3(aq) → 3A+(aq) + B(s)

Half Reaction

3A(s)⇒3A⁺(aq)+3e⁻

B⁺³(aq)+3e⁻⇒B(s)

n = 3 (3 electron transfer)

Q = the reaction quotient :

`\tt Q=([A^+]^3)/([B^(+3)])=(0.5^3)/(1.5.10^(-3))=83.3`

E cell :

`\tt E_(cell)=2-(0.0592)/(3)log~83.3\\\\E_(cell)=1.962~V`