Question

Identify from following the conjugate base of \([\text{Zn}(\text{H}_2\text{O})_4]^{2+}\)

• A. \([\text{Zn}(\text{H}_2\text{O})_4]^{2-}\,\text{NH}_3\)
• B. \([\text{Zn}(\text{H}_2\text{O})_3]^{2-}\)
• C. \([\text{Zn}(\text{H}_2\text{O})_3\text{OH}]^+\)
• D. \([\text{Zn}(\text{H}_2\text{O})\text{H}]^{3+}\)

Hint:

A conjugate base forms by removing one H+ from the acid, leaving charge one unit lower.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
In the Bronsted-Lowry idea, the conjugate base of an acid is what is left after the acid gives away one proton. The charge drops by 1 and one H is lost.

Step 2: Detailed Explanation
The acid is \([\text{Zn}(\text{H}_2\text{O})_4]^{2+}\). A coordinated water molecule loses \(\text{H}^+\) and becomes \(\text{OH}^-\):
\[ [\text{Zn}(\text{H}_2\text{O})_4]^{2+} \rightarrow [\text{Zn}(\text{H}_2\text{O})_3\text{OH}]^{+} + \text{H}^+ \]
So the conjugate base is \([\text{Zn}(\text{H}_2\text{O})_3\text{OH}]^+\). Option (B) has charge 2- and no hydroxide, which cannot arise by losing one proton, and (D) adds an H instead of removing it.

Final Answer:
The conjugate base is \([\text{Zn}(\text{H}_2\text{O})_3\text{OH}]^+\), option (C). \[ \boxed{[\text{Zn}(\text{H}_2\text{O})_3\text{OH}]^+} \]