Question

$Mn{O}_4^{-}+8H^{+}+5e^{-}\to M{n}^{2+}+4H_{2}O$
If $H^{+}$ concentration is decreased from 1 M to $10^{-4}$ M at $25°C$,

• A. the potential decreases by 0.38 V with decrease in oxidising power
• B. the potential increases by 0.38 V with increase in oxidising power
• C. the potential decreases by 0.25 V with decreases in oxidising power
• D. the potential decreases by 0.38 V without affecting oxidising power

Answer 1

Answer: (A)

$\Delta E=\frac{0.059}{5}log{\left[10^{-4}\right]}^8=-0.378V$