Question

Conjugate base for Brönsted acids \(H_2O\) and \( HF\) are

• A. \(OH^-\) and \(H_2F{+}\), respectively
• B. \(H_3O^+\) and \(F^-\), respectively
• C. \(OH^-\) and \(F^-\), respectively
• D. \(H_3O^+\) and \(H_2F^+\), respectively

Answer 1

The Correct Option is C

To determine the conjugate bases for the Brönsted acids \(H_2O\) and \(HF\), we first need to understand the concept of conjugate acid-base pairs. A conjugate base is formed when a Brönsted acid donates a proton (H⁺).

1. Consider the acid \(H_2O\):
   • As a Brönsted acid, \(H_2O\) can donate a proton, forming its conjugate base. When \(H_2O\) loses a proton, it becomes \(OH^-\):

   \(H_2O \rightarrow H^+ + OH^-\)

2. Now consider the acid \(HF\):
   • As a Brönsted acid, \(HF\) can donate a proton, forming its conjugate base. When \(HF\) loses a proton, it becomes \(F^-\):

   \(HF \rightarrow H^+ + F^-\)

Thus, the conjugate bases for \(H_2O\) and \(HF\) are \(OH^-\) and \(F^-\), respectively.

The correct answer is: \(OH^-\) and \(F^-\), respectively.

Let's rule out the other options:

• \(OH^-\) and \(H_2F^{+}\): \(H_2F^{+}\) is incorrect as a conjugate base. \(HF\) donates a proton forming \(F^-\).
• \(H_3O^+\) and \(F^-\): \(H_3O^+\) is the conjugate acid, not base, of \(H_2O\).
• \(H_3O^+\) and \(H_2F^+\): Both are incorrect as conjugate bases.