Question

Identify conjugate acid-base pair from following equilibrium reaction.
$\text{HSO}_{3(\text{aq})}^- + \text{H}_3\text{O}_{(\text{aq})}^+ \rightleftharpoons \text{H}_2\text{SO}_3 + \text{H}_2\text{O}$

• A. $\text{H}_2\text{SO}_3$ and $\text{HSO}_3^-$
• B. $\text{HSO}_3^-$ and $\text{H}_3\text{O}^+$
• C. $\text{H}_2\text{SO}_3$ and $\text{H}_2\text{O}$
• D. $\text{H}_3\text{O}^+$ and $\text{H}_2\text{SO}_3$

Hint:

Acid $\xrightarrow{-H^+}$ Conjugate Base; Base $\xrightarrow{+H^+}$ Conjugate Acid.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A conjugate acid-base pair consists of two species that differ by only one proton (\(\text{H}^+\)).
According to the Brønsted-Lowry theory, an acid donates a proton to become its conjugate base, while a base accepts a proton to become its conjugate acid.
Step 2: Key Formula or Approach:
The general relationship is:
\[ \text{Acid} \xrightarrow{-\text{H}^+} \text{Conjugate Base} \] \[ \text{Base} \xrightarrow{+\text{H}^+} \text{Conjugate Acid} \] Step 3: Detailed Explanation:
In the given reaction: \(\text{HSO}_{3(\text{aq})}^- + \text{H}_3\text{O}_{(\text{aq})}^+ \rightleftharpoons \text{H}_2\text{SO}_3 + \text{H}_2\text{O}\).
1. \(\text{HSO}_3^-\) accepts a proton to form \(\text{H}_2\text{SO}_3\). Here, \(\text{HSO}_3^-\) is the base and \(\text{H}_2\text{SO}_3\) is its conjugate acid.
2. \(\text{H}_3\text{O}^+\) donates a proton to form \(\text{H}_2\text{O}\). Here, \(\text{H}_3\text{O}^+\) is the acid and \(\text{H}_2\text{O}\) is its conjugate base.
Comparing the options, the pair \(\text{H}_2\text{SO}_3\) and \(\text{HSO}_3^-\) correctly represents a conjugate acid-base relationship.
Step 4: Final Answer:
The conjugate acid-base pair is \(\text{H}_2\text{SO}_3\) and \(\text{HSO}_3^-\).