Chapter 17, Problem 97QAP

For the cell:
$\text{Cr}|{\text{Cr}}^{3+}\Vert {\text{Co}}^{2+}|\text{Co}$
E° is 0.46 V. The same cell was prepared in the laboratory at standard conditions. The voltage obtained was 0.40 V. A possible explanation for the difference is
(a) the surface area of the chromium electrode was smaller than the cobalt electrode.
(b) the mass of the chromium electrode was larger than the mass of the cobalt electrode.
(c) the concentration of $\text{Cr}{\left({\text{NO}}_3\right)}_2$ solution used was less than 1.0 M.
(d) the concentration of $\text{Cr}{\left({\text{NO}}_3\right)}_2$ solution used was less than 1.0 M.
(e) the volume of $\text{Cr}{\left({\text{NO}}_3\right)}_2$ solution used was larger than the volume of $\text{Cr}{\left({\text{NO}}_3\right)}_2$ solution used.