Question

Give chemical reaction in support the following:

All the bonds in PCl₅ molecule are not equivalent.

Answer 1

1. PCl₅ has a trigonal bipyramidal shape with two types of bonds: three equatorial \[\ce{P - Cl}\] bonds and two axial \[\ce{P - Cl}\] bonds.
2. The axial bonds are longer (about 202 pm) and weaker, while equatorial bonds are shorter (about 197 pm) and stronger.
3. Due to this, all bonds in PCl₅ are not equivalent.
4. Chemical reaction showing this nonequivalence: 
   When PCl₅ reacts with water, it first breaks the axial bonds, forming PCl₃ and HCl, demonstrating the different bond strengths:
   \[\ce{PCl5 + H2O -> POCl3 + 2HCl}\]
   Here, PCl₅ dissociates through breaking axial \[\ce{P - Cl}\] bonds initially, confirming bond nonequivalence.