Question

\[{{N}_{2}}{{H}_{4}}\] is a strong baser than \[N{{H}_{3}}\]and \[{{N}_{3}}H\] is weaker acid than \[N{{H}_{3}}COOH.\]
(A) True
(B) False

Answer 1

Hint: To answer this question, we can use the concept of conjugate acid. For the correct answer of this question, we should know that conjugate acids are a type of acid that is formed when a base accepts a proton in solution.

Step by step answer:
We have to state that, whether \[{{N}_{2}}{{H}_{4}}\] is a strong baser than \[N{{H}_{3}}\] or not. We can answer this question by the concept conjugate acid-base pair. We should note that whenever an acid donates a proton, the acid changes into a base, and whenever a base accepts a proton, an acid is formed. An acid and a base which differ only by the presence or absence of a proton conjugate acid-base pair.
We should know about the theory of Bronsted-Lowry. It states that an acid is a proton donor and a base is a proton acceptor. We should know that, if an acid has given up a proton, the remaining part can be a proton acceptor, and thus a base. So, after this we say, an acid and a base are closely related to one another.
\[{{H}^{+}}+Base\rightleftarrows Conjugate\,acid\,ofBas{{e}^{+}}\]
\[Acid\rightleftarrows {{H}^{+}}+ConjugatebaseofAci{{d}^{-}}\]
We should know that \[N{{H}_{3}}\] is a weak base. In other words, when it donates a proton, the weak acid NH4+ is transformed into a weak base\[N{{H}_{3}}\].
And by using the above theory of conjugate acid base we can describe the above statement. By using conjugate base concept we can say that \[{{N}_{2}}{{H}_{4}}\]​ is not stronger base than \[N{{H}_{3}}\]​. Because, \[N{{H}_{3}}\] conjugate acid \[N{{H}_{3}}^{+}~\] is more stable and acidic than \[{{N}_{2}}{{H}_{5}}^{+}.\] ​In the same way we can say that \[{{N}_{3}}H\] is not weaker acid than \[N{{H}_{3}}COOH.\]. It is stronger acid that \[N{{H}_{3}}COOH.\]

So, the above statement that is given in question is not true. It is a false statement.

Note:
The first concept on acid and base was given in 1884. Arrhenius stated that all acids have \[{{\text{H}}^{+}}\] ions and bases have \[\text{O}{{\text{H}}^{-}}\] ions. Thus, he considered all substances giving \[{{\text{H}}^{+}}\] and \[\text{O}{{\text{H}}^{-}}\] ions are acids and bases respectively. And then Bronsted, Lowry and Lewis give different concepts about acid and base.
We should know that Bronsted-Lowry's concept focused on the proton and he stated that:
(i) Acids as proton donors,
(ii) Bases as proton acceptors,
We should also know about Lewis theory, he focused on the electrons and defined that:
(i) Acids as electrophiles,
(ii) Bases as nucleophiles.