1. **Problem Statement:** Calculate the cell potential for the reaction $$\mathrm{Cr_2O_7^{2-} + I^- \leftrightarrow Cr^{3+} + I_2}$$ under non-standard conditions with concentrations: $$[\mathrm{Cr^{3+}}] = 1.0 \times 10^{-5}$$, $$[\mathrm{Cr_2O_7^{2-}}] = 2.0$$, $$[\mathrm{H^+}] = 1.0$$, $$[\mathrm{I^-}] = 1.0$$.
2. **Balanced Redox Reaction:**
$$\mathrm{Cr_2O_7^{2-} + 14H^+ + 6I^- \leftrightarrow 2Cr^{3+} + 3I_2 + 7H_2O}$$
3. **Reaction Quotient (Q):**
$$Q = \frac{[\mathrm{Cr^{3+}}]^2}{[\mathrm{Cr_2O_7^{2-}}][\mathrm{H^+}]^{14}[\mathrm{I^-}]^6}$$
4. **Substitute given concentrations:**
$$Q = \frac{(1.0 \times 10^{-5})^2}{2.0 \times (1.0)^{14} \times (1.0)^6} = \frac{1.0 \times 10^{-10}}{2.0} = 5.0 \times 10^{-11}$$
5. **Nernst Equation:**
$$E = E^0 - \frac{0.0592}{n} \log Q$$
where $$E^0 = 0.796\,V$$ and $$n = 6$$ (number of electrons transferred).
6. **Calculate:**
$$E = 0.796 - \frac{0.0592}{6} \log(5.0 \times 10^{-11})$$
$$= 0.796 - 0.009867 \log(5.0 \times 10^{-11})$$
7. **Evaluate logarithm:**
$$\log(5.0 \times 10^{-11}) = \log 5.0 + \log 10^{-11} = 0.6990 - 11 = -10.3010$$
8. **Substitute back:**
$$E = 0.796 - 0.009867 \times (-10.3010)$$
$$= 0.796 + 0.1016 = 0.8976\,V$$
9. **Final answer:**
$$\boxed{E_{cell} = 0.898\,V}$$
Cell Potential 56Ebcc
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