Q. Strongest Bronsted base among the following anions is
Chhattisgarh PMTChhattisgarh PMT 2006
Solution:
Conjugate base of weak acid is always strong
Conjugate base
Acid
Oxidation sate of $Cl$
$ClO^-$
$HClO$
$+I$
$ClO^-_{2}$
$HClO_2$
$+III$
$ClO^-_{3}$
$HClO_3$
$+V$
$ClO^-_{4}$
$HClO_4$
$+VII$
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 $ClO^−$
| Conjugate base | Acid | Oxidation sate of $Cl$ |
|---|---|---|
| $ClO^-$ | $HClO$ | $+I$ |
| $ClO^-_{2}$ | $HClO_2$ | $+III$ |
| $ClO^-_{3}$ | $HClO_3$ | $+V$ |
| $ClO^-_{4}$ | $HClO_4$ | $+VII$ |