The standard reduction potential values of three metallic cations, X, Y and Z are +0.52, -3.03 and - — Electrochemistry Chemistry Question

💡 Solution & Explanation

Step 1 - Conceptual Understanding of Reducing Power and Standard Reduction Potential The reducing power of a metal is inversely proportional to its standard reduction potential: $$\text{Reducing Power} \propto \frac{1}{E^\circ_{\text{red}}}$$ A highly negative (lower) standard reduction potential means the metal has a very strong tendency to lose electrons, making it a powerful reducing agent. Step 2 - Analyze the Given Standard Reduction Potential Values We are given: * $E^\circ(\ce{X^{n+}/X}) = +0.52\text{ V}$ * $E^\circ(\ce{Y^{n+}/Y}) = -3.03\text{ V}$ * $E^\circ(\ce{Z^{n+}/Z}) = -1.18\text{ V}$ Step 3 - Determine the Order of Reducing Power Comparing the values from lowest to highest: $$-3.03\text{ V} < -1.18\text{ V} < +0.52\text{ V}$$ $$E^\circ(\ce{Y^{n+}/Y}) < E^\circ(\ce{Z^{n+}/Z}) < E^\circ(\ce{X^{n+}/X})$$ Since reducing power increases as the reduction potential becomes more negative: $$\text{Reducing Power: } \text{Y} > \text{Z} > \text{X}$$ Step 4 - Evaluation of Options * **Option (A)** $\text{Y} > \text{Z} > \text{X}$ — correct, matches our derived order. * **Option (B)** $\text{X} > \text{Y} > \text{Z}$ — incorrect, ranks X (positive potential) as strongest. * **Option (C)** $\text{Z} > \text{Y} > \text{X}$ — incorrect, incorrectly ranks Z above Y. * **Option (D)** $\text{Z} > \text{X} > \text{Y}$ — incorrect, ranks Y as weakest. $$\text{Correct Answer: } \boxed{\text{A}}$$