Among the following, the number of halide(s) which is/are inert to hydrolysis is_____. (a) BF (b) Si — p Block Elements Chemistry Question

💡 Solution & Explanation

**Step 1: Understand hydrolysis resistance** A halide is inert to hydrolysis if it resists reaction with water. This depends on: - Bond strength (strong bonds = more inert) - Ability to expand the octet (relevant for non-metals) - Steric protection around the central atom **Step 2: Analyze BF₃** BF₃ has strong B-F bonds, but boron is electron-deficient (only 6 electrons). It readily accepts water molecules and undergoes hydrolysis: BF₃ + H₂O → B(OH)₃ + HF **Hydrolyzes** ✗ **Step 3: Analyze SiCl₄** Silicon can expand its octet and form 5-6 coordinate complexes. Water easily attacks the Si center: SiCl₄ + 3H₂O → SiO₂ + 4HCl **Hydrolyzes** ✗ **Step 4: Analyze PCl₅** Phosphorus can expand its octet. The P-Cl bonds are polar and susceptible to nucleophilic attack by water: PCl₅ + 4H₂O → H₃PO₄ + 5HCl **Hydrolyzes** ✗ **Step 5: Analyze SF₆** Sulfur is surrounded by six highly electronegative fluorine atoms in octahedral geometry. The strong S-F bonds and steric bulk create a highly inert structure. Water cannot effectively attack the sulfur center. **Does NOT hydrolyze** ✓ **Step 6: Count inert halides** Only SF₆ is inert to hydrolysis. Therefore, the answer is 1.00.