Question

Cl₂O₇ is the anhydride of which acid?

• A. Hypochlorous acid (HClO)
• B. Chlorous acid (HClO₂)
• C. Chloric acid (HClO₃)
• D. Perchloric acid (HClO₄)

Hint:

Higher oxides of chlorine (like Cl\textsubscript{2}O\textsubscript{7}) form oxyacids with higher oxidation states. Cl\textsubscript{2}O\textsubscript{7} corresponds to perchloric acid, where Cl is in +7 state.

Answer 1

The Correct Option is D

Step 1: Acid Anhydride Definition
An acid anhydride is an oxide that, upon reacting with water, produces an oxyacid. This is frequently observed with non-metals like chlorine. Step 2: Oxide Identification and Hydrolysis Reaction
The given molecular formula, Cl₂O₇, represents chlorine heptoxide. Its reaction with water is: \[ \text{Cl}_2\text{O}_7 + \text{H}_2\text{O} \rightarrow 2 \text{HClO}_4 \] This reaction generates perchloric acid (HClO₄), a strong acid in which chlorine has a +7 oxidation state.
Step 3: Conclusion
Cl₂O₇ serves as the anhydride of perchloric acid (HClO₄). \[ \boxed{\text{Cl}_2\text{O}_7 \rightarrow \text{Anhydride of } \text{HClO}_4} \]