# Which is not amphoteric? Option 1) $HSO_{4}^{-}$ Option 2) $HCO_{3}^{-}$ Option 3) $H_{2}PO_{4}^{-}$ Option 4) $HCOO^{-}$

P Plabita

As learnt in

Ionization reaction of dibasic acid -

$H_{2}X(aq)\rightleftharpoons H^{+}(aq)+H\bar{X}(aq)$

$\bar{H}X(aq)\rightleftharpoons H^{+}(aq)+X^{2-}(aq)$

- wherein

$K_{a1}=\frac{[H^{+}]\:[\bar{H}X]}{[H_{2}X]}$

$K_{a2}=\frac{[H^{+}]\:[X^{2-}]}{[{H}X^{-}]}$

$K_{a1}\:and\:K_{a2}$   are called first and second ionization constant.

Of all the species given, $HCOO^{-}$ is the only one that cannot donate a proton and act as an acid. All of these can accept a proton thereby acting as a lease.

Option 1)

$HSO_{4}^{-}$

This solution is incorrect.

Option 2)

$HCO_{3}^{-}$

This solution is incorrect.

Option 3)

$H_{2}PO_{4}^{-}$

This solution is incorrect.

Option 4)

$HCOO^{-}$

This solution is correct.

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