Question

For which of these redox pairs, the reduction potential vary with pH

• A. $Am{O}_2^{2+}/Am{O}_2^{+}$
• B. $Am{O}_2^{2+}/A{m}^{4+}$
• C. $Mn{O}_4^{-}/M{n}^{2+}$
• D. $Z{n}^{2+}/Zn$

Answer 1

Answer: (B), (C)

The half reaction involves H${}^{+}$ only in
$4H^{+}+Am{O}_2^{2+}+2e\to A{m}^{4+}+2H_{2}O$
and $Mn{O}_4^{-}+8H^{+}+5e\to M{n}^{2+}+4H_{2}O$
(according to oxygen balance)