Question

Identify the conjugate bases of \(\text{H}_3\text{PO}_3\) and \(\text{H}_2\text{SO}_4\) respectively from following.

• A. \(\text{HPO}_3^{2-}\) and \(\text{SO}_4^{2-}\)
• B. \(\text{HPO}_3^{2-}\) and \(\text{HSO}_4^-\)
• C. \(\text{H}_2\text{PO}_3^-\) and \(\text{HSO}_4^-\)
• D. \(\text{PO}_3^{3-}\) and \(\text{SO}_4^{2-}\)

Hint:

A conjugate base is formed by removing one proton, and H3PO3 is only dibasic.

Answer 1

The Correct Option is C

Step 1: Rule:
Conjugate base = acid minus one proton.

Step 2: Apply:
$\text{H}_3\text{PO}_3$ losing one H leaves $\text{H}_2\text{PO}_3^-$ with a $-1$ charge.
$\text{H}_2\text{SO}_4$ losing one H leaves $\text{HSO}_4^-$.
The species $\text{SO}_4^{2-}$ and $\text{HPO}_3^{2-}$ are the conjugate bases of $\text{HSO}_4^-$ and $\text{H}_2\text{PO}_3^-$, so they are second-stage products.

Final Answer:
The correct pair is $\text{H}_2\text{PO}_3^-$ and $\text{HSO}_4^-$, option (C). \[ \boxed{\text{H}_2\text{PO}_3^- \text{ and } \text{HSO}_4^-} \]