Question

A hydride of nitrogen which is acidic is:
A. $\text{N}{{\text{H}}_{3}}$
B. ${{\text{N}}_{2}}{{\text{H}}_{2}}$
C. ${{\text{N}}_{2}}{{\text{H}}_{4}}$
D. ${{\text{N}}_{3}}\text{H}$

Answer 1

As we know that acidic molecules can easily release the hydrogen ions. So, we have to compare the strength of each molecule of hydride of nitrogen to state which hydride is more acidic.

Complete step by step solution:
- In the given question, we have to explain which hydride of nitrogen is acidic.
- Now, as we know that compounds which are acidic can donate the hydrogen ions whereas the basic compounds can donate hydroxyl ions.
- Moreover, when a compound is considered as acidic it has a tendency to accept electrons but the more is the positive charge on the molecule more will be its acidity.
- Because the more is the positive charge on the molecule the more it will tend to accept the electrons and more it will be acidic.
- So, we will calculate the oxidation state of nitrogen in each molecule:
In ammonia, $\text{N}{{\text{H}}_{3}}$:
$\text{x + 3 = 0; x = -3}$
In Diazene or ${{\text{N}}_{2}}{{\text{H}}_{2}}$,
$\text{2x + 2 = 0; x = -1}$
In hydrazine or ${{\text{N}}_{2}}{{\text{H}}_{4}}$,
$\text{2x + 4 = 0; x = -2}$
In hydrazoic acid or ${{\text{N}}_{3}}\text{H}$,
$\text{3x + 1 = 0; x = -1/3}$
- So, as we can see that the hydrazoic acid has the least negative and more positive charge on nitrogen.
- Due to which it will be considered as the most acidic hydride of nitrogen whereas others are basic.

Therefore, option D is the correct answer.

Note: Hydrogen azide and azomite are other names for hydrazoic acid which is a volatile and colourless compound. Hydrazoic acid is very fatal or harmful for us because when it is inhaled it can cause a severe headache because it is highly toxic.