Reduction potential of ions are given below: \[ \begin{array}{ccc} \mathrm{ClO}_{4}^{-} & \mathrm{IO}_{4}^{-} & \mathrm{BrO}_{4}^{-} \\ \mathrm{E}^{\circ}=1.19 \mathrm{~V} & \mathrm{E}^{\circ}=1.65 \mathrm{~V} & \mathrm{E}^{\circ}=1.74 \mathrm{~V} \end{array} \] The correct order of their oxidising power is:

(B) $\mathrm{BrO}_{4}^{-}>\mathrm{IO}_{4}^{-}>\mathrm{ClO}_{4}^{-}$

(A) $\mathrm{ClO}_{4}^{-}>\mathrm{IO}_{4}^{-}>\mathrm{BrO}_{4}^{-}$

(C) $\mathrm{BrO}_{4}^{-}>\mathrm{ClO}_{4}^{-}>\mathrm{IO}_{4}^{-}$

(D) $\mathrm{IO}_{4}^{-}>\mathrm{BrO}_{4}^{-}>\mathrm{ClO}_{4}^{-}$

JEE Main · 2024 · 30 Jan 2024 · Shift 2 · Redox Reactions and Electrochemistry

Reduction potential of ions are given below:

ClO_{4}^{-} E^{\circ} = 1.19 V IO_{4}^{-} E^{\circ} = 1.65 V BrO_{4}^{-} E^{\circ} = 1.74 V

The correct order of their oxidising power is:

Answer: (B)

The strength of an oxidising agent tracks its standard reduction potential directly: a more positive

E^{\circ}

means a greater tendency for the species to be reduced, i.e. a stronger oxidiser. Since

E^{\circ} (BrO_{4}^{-}) = 1.74 V > E^{\circ} (IO_{4}^{-}) = 1.65 V > E^{\circ} (ClO_{4}^{-}) = 1.19 V

, the oxidising power follows

BrO_{4}^{-} > IO_{4}^{-} > ClO_{4}^{-}

JEE Main · 2024 · 30 Jan 2024 · Shift 2 · Single correct option