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.

Respuesta :

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  

[tex]\rm E = E ^ o -\dfrac {RT} {nF} lnQ[/tex]

For temperature T = 298 K,  

[tex]\rm E = E ^ o -\dfrac {0.0592V} {n} log \: Q[/tex]

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  :

[tex]\tt Q=\dfrac{[A^+]^3}{[B^{+3}]}=\dfrac{0.5^3}{1.5.10^{-3}}=83.3[/tex]

E cell :

[tex]\tt E_{cell}=2-\dfrac{0.0592}{3}log~83.3\\\\E_{cell}=1.962~V[/tex]