Chapter 24, Problem 60IAE

Interpretation Introduction

Interpretation:

To determine the value of E° for the following reaction. The reaction is −

${[{\text{Co(en)}}_{\text{2}}]}^{3+}+e^{-}\to {[{\text{Co(en)}}_{\text{2}}]}^{2+}$

To prove that complex ${[{\text{Co(en)}}_{\text{3}}]}^{3+}$ is stable in water and $C{o}^{3+}(aq)$ is not. The data is given as-

${[Co{(H_{2}O)}_6]}^{3+}+e^{-}\to {[{\text{Co(H}}_{\text{2}}{\text{O)}}_{\text{6}}]}^{2+},E°=1.82V$

${[{\text{Co(H}}_{\text{2}}{\text{O)}}_{\text{6}}]}^{2+}+3en\to {[{\text{Co(en)}}_{\text{3}}]}^{2+}+6H_{2}O(l),log{\beta }_3=12.18$

${[\mathrm{Co}{(H_{2}O)}_6]}^{3+}+3en\to {[{\text{Co(en)}}_{\text{3}}]}^{3+}+6H_{2}O(l),log{\beta }_3=47.30$

Concept introduction:

Nernst equation is represented as follows:

$\log K_f=\frac{nE{°}_{formation}}{0.0592}$

Or,

$nE{°}_{formation}=0.0592\log K_f$

Here, n is number of electron transfer in the reaction.