The number of Cl = O bonds in perchloric acid is, “…………..” — p Block Elements Chemistry Question

💡 Solution & Explanation

**Step 1: Identify the molecular formula of perchloric acid** Perchloric acid is HClO₄. **Step 2: Determine the structure** Perchloric acid has chlorine as the central atom bonded to four oxygen atoms, with one oxygen bearing a hydrogen (O-H group). The structure is: ``` O ‖ O = Cl = O | O-H ``` **Step 3: Identify Cl=O bonds** Cl=O double bonds are present where chlorine forms double bonds with oxygen atoms (not the hydroxyl oxygen). **Step 4: Count the double bonds** In perchloric acid's resonance structures, three of the four Cl-O bonds are equivalent and exist as a combination of double and single bonds due to resonance. The standard representation shows three Cl=O double bonds (with one Cl-O single bond to the hydroxyl group). **Step 5: Account for resonance contribution** Due to resonance stabilization, the three Cl-O bonds (excluding the O-H bond) each have partial double bond character. The formal counting method identifies **3 Cl=O bonds**. Therefore, the answer is **3.00**.