Question

Consider the cell:
$Cd\left(s\right)|C{d}^{2+}\left(1.0M\right)||C{u}^{2+}\left(0.1M\right)|Cu\left(s\right)$
If we wish to make a cell with a more positive voltage using the same substance, we should:

• A. increase both $\left[C{d}^{2+}\right]$ and $\left[C{u}^{2+}\right]$ to 2.0 M
• B. decrease the $\left[C{d}^{2+}\right]$ to 0.1 M
• C. increase the $\left[C{u}^{2+}\right]$ to 1.0 M
• D. decrease both the $\left[C{d}^{2+}\right]$ and $\left[C{u}^{2+}\right]$ to 0.01 M

Answer 1

Answer: (B), (C)

The correct options are
B decrease the $\left[C{d}^{2+}\right]$ to 0.1 M
C increase the $\left[C{u}^{2+}\right]$ to 1.0 M

Redox reaction:

$Cd\left(s\right)\to C{d}^{2+}+2e$

$C{u}^{2+}+2e\to Cu\left(s\right)$
$E_{cell}=E_{cell}^{\ominus }-\frac{0.059}{2}log\frac{\left[C{d}^{2+}\right]}{\left[C{u}^{2+}\right]}$
$E_{cell}$ increases when conditions as in (B) and (C) are made.