Question

Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidising power.

Ion	$ClO^-_4$	$IO^-_4$	$BrO^-_4$
Reduction potential $E^{\circ}/V$	$E^{\circ}=1.19\,V$	$E^{\circ}=1.65\,V$	$E^{\circ}=1.74\,V$

• A. $ClO^{-}_{4} > IO^{-}_{4} > BrO^{-}_{4}$
• B. $IO^{-}_{4} > BrO^{-}_{4} > ClO^{-}_{4}$
• C. $BrO^{-}_{4} >IO^{-}_{4} > ClO^{-}_{4}$
• D. $BrO^{-}_{4} > ClO^{-}_{4} > IO^{-}_{4}$

Answer 1

Answer: (C)

Higher the reduction potential value, greater is the tendency to undergo reduction and stronger is the oxidising power.
$\begin{matrix}&BrO^{-}_{4}&>&IO^{-}_{4}&>&ClO^{-}_{4}\\ E^{\circ}/V&1.74&&1.65&&1.19\end{matrix}$