Question

In which reactions does $N{H_3}$ behave as a Bronsted-Lowry acid?
$2N{H_3}\xrightarrow{{}}NH_2^ - + NH_4^ +$
$HSO_4^ - + N{H_3}\xrightarrow{{}}SO_4^{2 - } + NH_4^ +$
$A{g^ + } + 2N{H_3}\xrightarrow{{}}{\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$
a.) 1, 2, and 3 are correct
b.) 1 and 2 only are correct
c.) 2 and 3 only are correct
d.) 1 only is correct

Answer 1

According to the Bronsted-Lawry concept of an acid and base, acids are defined as an entity that can donate a proton ( ${H^ + }$ ), and among the following reactions given to us $N{H_3}$ only donates ${H^ + }$ in the first reaction.

Complete step by step answer:
To understand the solution, we first need to understand what the Bronsted-Lawry concept of acid and base is.
According to the Bronsted-Lawry concept of an acid and base, acids are defined as an entity that can donate a proton ( ${H^ + }$ ) and bases are defined as an entity that can accept a proton. The whole concept of Bronsted-Lowry revolves around the concept of donating or accepting an electron which is unlike the traditional concept of acid and base (i.e. the Arrhenius concept of acid and base, in which acid is an entity that donates ${H^ + }$ and the base is defined as an entity that can donate $O{H^ - }$ )
In the problem, we are given the following reactions
$2N{H_3}\xrightarrow{{}}NH_2^ - + NH_4^ +$
$HSO_4^ - + N{H_3}\xrightarrow{{}}SO_4^{2 - } + NH_4^ +$
$A{g^ + } + 2N{H_3}\xrightarrow{{}}{\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$
We can see clearly that $N{H_3}$ only donates ${H^ + }$ in the first reaction. In the reaction, it accepts ${H^ + }$ ion, and in the third reaction no transfer of ${H^ + }$ takes place.
So, the correct answer is “Option D”.

Note: In the solution above we discussed both the Bronsted-Lawry concept of acid and base and also the Arrhenius concept of acid and base but both of these had some flaws. We also have one more concept of acid and base, which is the Lewis concept which states that is an entity that can accept an electron pair and base is an entity that can donate a pair of electrons.