Question

Which of the following pairs of species is not a conjugate acid-base pair?

A) HOCl, OCl-
B) HNO2, NO2+
C) O2-, OH-
D) HSO4-, SO42-
E) H2CO3, HCO3

Answer 1

Answer : The option (c) is not a conjugate acid-base pair.

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,

`HOCl+H_2O\rightleftharpoons OCl^-+H_3O^+`

In this reaction,
`HOCl/OCl^-` are act as a conjugate acid-base pair.

(b) The equilibrium reaction will be,

`HNO_2+H_2O\rightleftharpoons NO_2^-+H_3O^+`

In this reaction,
`HNO_2/NO_2^-` are act as a conjugate acid-base pair.

(c) The equilibrium reaction will be,

`O^(2-)+H_2O\rightleftharpoons OH^-+OH^-`

In this reaction,
`O^(2-)/OH^-` are not act as a conjugate acid-base pair.

(d) The equilibrium reaction will be,

`HSO_4^-+H_2O\rightleftharpoons SO_4^(2-)+H_3O^+`

In this reaction,
`HSO_4^-/SO_4^(2-)` are act as a conjugate acid-base pair.

(e) The equilibrium reaction will be,

`H_2CO_3+H_2O\rightleftharpoons HCO_3^(-)+H_3O^+`

In this reaction,
`H_2CO_3/HCO_3^(-)` are act as a conjugate acid-base pair.

Hence, from this we conclude that, the option (c) is not a conjugate acid-base pair but it is a act as conjugate base-acid pair.