Question

Which one of the following pairs of acids and conjugate bases is incorrectly labeled or incorrectly matched? Acid Conjugate Base (a) HF F– (b) HClO ClO– (c) H2O OH– (d) NH4+ NH2– (e) H3O+ H2O

Answer 1

Answer : The incorrect option is, (d) $NH_4^+/NH_2^-$

Explanation :

According to the Bronsted Lowry concept, Bronsted Lowry-acid is a substance that donates one or more hydrogen ion in a reaction and Bronsted Lowry-base is a substance that accepts one or more hydrogen ion in a reaction.

Or we can say that, conjugate acid is proton donor and conjugate base is proton acceptor.

(a) The equilibrium reaction will be,

$HF+H_2O\rightleftharpoons F^-+H_3O^+$

In this reaction, $HF$ is an acid that donate a proton or hydrogen to $H_2O$ base and it forms $F^-$ and $H_3O^+$ are conjugate base and acid respectively.

In this reaction, $HF/F^-$ are act as a conjugate acid-base.

(b) The equilibrium reaction will be,

$HClO+H_2O\rightleftharpoons ClO^-+H_3O^+$

In this reaction, $HClO$ is an acid that donate a proton or hydrogen to $H_2O$ base and it forms $ClO^-$ and $H_3O^+$ are conjugate base and acid respectively.

In this reaction, $HClO/ClO^-$ are act as a conjugate acid-base.

(c) The equilibrium reaction will be,

$H_2O+H_2O\rightleftharpoons OH^-+H_3O^+$

In this reaction, $H_2O$ is an acid that donate a proton or hydrogen to

In this reaction, $H_2O/OH^-$ are act as a conjugate acid-base.

(d) The equilibrium reaction will be,

$NH_4^++H_2O\rightleftharpoons NH_3+H_3O^+$

In this reaction, $NH_4^+$ is an acid that donate a proton or hydrogen to $H_2O$ base and it forms $NH_3$ and $H_3O^+$ are conjugate base and acid respectively.

In this reaction, $NH_4^+/NH_3$ are act as a conjugate acid-base.

(e) The equilibrium reaction will be,

$H_3O^++H_2O\rightleftharpoons H_2O+H_3O^+$

In this reaction, $H_3O^+$ is an acid that donate a proton or hydrogen to $H_2O$ base and it forms

In this reaction, $H_3O^+/H_2O$ are act as a conjugate acid-base.

From this we conclude that that, $NH_4^+/NH_2^-$ pairs of acids and conjugate bases is incorrectly labeled or incorrectly matched.

Hence, the incorrect option is, (d) $NH_4^+/NH_2^-$