Question

Hydrazoic acid, HN₃ is a weak acid. What is the conjugate base of hydrazoic acid?

1) N₃-
2) NH₄⁺+
3) H₂O
4) H₃O+

Answer 1

The conjugate base of hydrazoic acid (HN₃) is the azide ion (N₃⁻), which is option 1) N₃⁻. This follows from the Brønsted-Lowry theory, which states that the conjugate base is formed when an acid donates a proton.

Step-by-step explanation:

The conjugate base of hydrazoic acid (HN₃) is formed when the acid donates a proton (H+) to water. According to Brønsted-Lowry acid-base theory, a conjugate base is what remains of the acid molecule after a proton has been lost. In the case of hydrazoic acid, the removal of a proton from HN₃ results in the formation of N₃-.

HN₃ (aq) → H¹ (aq) + N₃¹ (aq)

Answering the student's question, the conjugate base of hydrazoic acid is option 1) N₃⁻. This is because hydrazoic acid (HN₃) ionizes to yield the proton and azide ion (N₃⁻) in aqueous solution, where the azide ion acts as the conjugate base. Also, the strength of an acid is inversely related to the strength of its conjugate base; weaker acids tend to have stronger conjugate bases.

Answer 2

The conjugate base of hydrazoic acid (HN₃) is N₃-.Thus,the correct option is 1.

Step-by-step explanation:

Hydrazoic acid (HN₃) is a weak acid that can donate a proton (H⁺) in aqueous solution. When HN₃ donates a proton, it forms its conjugate base, which is N₃-. The dissociation reaction of hydrazoic acid can be represented as follows:

`\[ HN₃ \rightleftharpoons H⁺ + N₃^- \]`

In this reaction, hydrazoic acid (HN₃) loses a proton (H⁺) to become N₃-, which is the conjugate base. The equilibrium expression for this reaction is given by the acid dissociation constant
`(\(K_a\))`:

`\[ K_a = ([H⁺][N₃^-])/([HN₃]) \]`

Since hydrazoic acid is a weak acid, the concentration of N₃- in the dissociation equilibrium is significant, confirming that N₃- is indeed the conjugate base. The reaction shifts to the right, and N₃- is formed as the conjugate base of hydrazoic acid.

In summary, the conjugate base of hydrazoic acid is N₃- because it results from the loss of a proton by hydrazoic acid in a reversible dissociation reaction. This process is in accordance with the principles of acid-base chemistry and the definition of conjugate acids and bases.

Therefore,the correct option is 1.