Question

What is the conjugate acid of $NH_{4}^{+}$in the reaction $NH_{4}^{+}+O{{H}^{-}}\xrightarrow{{}}{{H}_{2}}O+N{{H}_{3}}$ ?

Answer 1

Hint : We know that we need to use the concept of Bronsted-Lowry theory for acids and acids, where an acid donates a proton and an acid accepts a proton. The conjugate acid can be defined as the product formed from a Bronsted-Lowry acid by donating a proton.

Complete Step By Step Answer:
First, let us understand the concept of acid and acid from the BronstedLowry theory. As per the theory, a compound that donates a proton in a reaction is said to be acid and is known as Bronsted-Lowry acid. Similarly, a compound that accepts a proton in a reaction is said to be acting as an acid and is known as Bronsted-Lowry acid. Now, let us understand the concept of conjugate acid and acid. A conjugate acid is the product of a reaction that is formed from a Bronsted-Lowry acid by donating a proton. A conjugate acid is the product of a reaction that is formed from a Bronsted-Lowry acid by accepting a proton. Here, we are required to find the conjugate acid of $NH_{4}^{+}$.
And the conjugate acid of ammonia is ammonium ion.....for the conjugate acid/base, we simply add OR subtract a proton to the parent acid/base. The conjugate base of ammonia this does not occur in water, but it is conceived to occur in liquid ammonia. And what is the conjugate base of this conjugate base and the conjugate base of that conjugate base is nitride trianion ${{N}^{3-}}$.
The conjugate BASE of ammonium ion, $NH_{4}^{+}$is ammonia, $N{{H}_{3}}.$

Note :
Remember that a conjugate base is formed from a compound that acts as an acid. Similarly, a conjugate acid is formed from the compound that acts as a base. As an acid donates a proton, the charge of the conjugate base will always be one less than the acid. Similarly for a base, the charge of the conjugate acid is always one more than the base.