Question
What will be standard cell potential of galvanic cell with the following reaction?
$$2C{r_{\left( s \right)}} + 3Cd_{\left( {aq} \right)}^{2 + } \to 2Cr_{\left( {aq} \right)}^{3 + } + 3C{d_{\left( s \right)}}$$
$$\left[ {{\text{Given:}}\,E_{\frac{{C{r^{3 + }}}}{{Cr}}}^ \circ = - 0.74\,V\,\,{\text{and}}\,\,E_{\frac{{C{d^{2 + }}}}{{Cd}}}^ \circ = - 0.40\,V} \right]$$
A.
0.74 $$V$$
B.
1.14 $$V$$
C.
0.34 $$V$$
D.
- 0.34 $$V$$
Answer :
0.34 $$V$$
Solution :
$$\eqalign{
& E_{{\text{cell}}}^ \circ = E_{{\text{cathode}}}^ \circ - E_{{\text{anode}}}^ \circ \cr
& E_{{\text{cell}}}^ \circ = E_{\frac{{C{d^{2 + }}}}{{Cd}}}^ \circ - E_{\frac{{C{r^{3 + }}}}{{Cr}}}^ \circ \cr
& \,\,\,\,\,\,\,\,\,\,\,\, = - 0.40 - \left( { - 0.74} \right) \cr
& \,\,\,\,\,\,\,\,\,\,\,\, = + 0.34\,V \cr} $$