Take $2.303 RT / F = 0.0591 V$ at 298 K. Which of the following statements are correct?

A $KMnO X_{4}$ is a stronger oxidising agent in acidic solution than in neutral solution
BThe potential of the $H X^{+} / H X_{2}$ electrode (1 bar) falls by $0.0591 V$ for every unit rise in pH
CThe potential of the $Cl X_{2} / Cl X^{-}$ couple falls as pH increases
DAt pH 14 the potential of the $H X^{+} / H X_{2}$ electrode (1 bar) is about $- 0.83 V$

Answer: A, B, D

The

MnO X_{4} X^{-} / Mn X^{2 +}

potential contains

[H X^{+}]^{8}

, so it is higher (stronger oxidant) at low pH (A). For the hydrogen electrode

E = - 0.0591 pH

(B), which at pH 14 gives

- 0.827 V

(D).

Cl X_{2} + 2 e X^{-} 2 Cl X^{-}

involves no

H X^{+}

, so its potential does not depend on pH (C is wrong).