Question

Strongest Bronsted base among the following anions is

• A. $Cl{O}^{-}$
• B. $Cl{O}_2^{-}$
• C. $Cl{O}_3^{-}$
• D. $Cl{O}_4^{-}$

Answer 1

Answer: (A)

Conjugate base of weak acid is always strong

Conjugate base	Acid	Oxidation sate of $Cl$
$Cl{O}^{-}$	$HClO$	$+I$
$Cl{O}_2^{-}$	$HCl{O}_2$	$+III$
$Cl{O}_3^{-}$	$HCl{O}_3$	$+V$
$Cl{O}_4^{-}$	$HCl{O}_4$	$+VII$

In case of oxyacids of same element, as oxidation number of element increases their acidic strength increases.
$HClO$ is weakest acid, hence its conjugate base is strongest $Cl{O}^{-}$