Question

Conjugate base of $O{H^ - }$ is-
A.${H_2}O$
B.${H_3}{O^ + }$
C.${H^ + }$
D.${O^{2 - }}$

Answer 1

Hint- A conjugate acid contains one more H molecule and one more + charge than the base that framed it. A conjugate base contains one less H molecule and one more - charge than the acid that framed it.

Complete answer:

As per Bronsted and Lowry hypothesis, Bronsted–Lowry hypothesis, likewise called proton hypothesis of acids and bases, a hypothesis, presented independently in 1923 by the Danish physicist Johannes Nicolaus Bronsted and the English scientist Thomas Martin Lowry, expressing that any compound that can transfer a proton to some other compound is an acid, and the compound that accepts the proton is a base. A proton is an atomic molecule with a unit positive electrical charge; it is represented by the symbol H+ in light of the fact that it comprises the nucleus of a hydrogen atom.
Thus, the self-created acid base pair because of acceptance or donation of protons is known as conjugate acid base pair.
Conjugate acids and bases differ by proton. Thus, every acid has one excess proton than its conjugate base. If $O{H^ - }$ loses proton, then ${O^{2 - }}$ ion is obtained.
Hence, option D is the correct option.

Note: To get the conjugate acid, we have to add one H+ ion to the entity. So, the conjugate acid if $O{H^ - }$ will be ${H_2}O$. Self-made acid base pair as a result of acceptance or donation of proton is known as conjugate acid base pair.