Question

Place the following in order of increasing F-A-F bond angle, where A represents the central atom in each molecule. PF3 OF2 PF4+

Answer 1

Draw the Lewis structures of PF3, OF2 and PF4 as follows: FPF: The centreal P in PF3 contains 4 electron pairs. Thus it undergoes sp3 hybridisatiorn Since, it has 3 bond pairs and 1 lone pair. The molecular geometry is pyramidal. The expected F-P-F bond angle is 109.5°. The centreal O in OF2 contains 4 electron pairs. Thus it undergoes sp3 hybridisation Since, it has 2 bond pairs and 2 lone pair. The molecular geometry is angular. The expected F-O-F bond angle is 109.5° The centreal P in PF3 contains 4 electron pairs. Thus it undergoes sp3 hybridisatiorn Since, it has 4 bond pairs. The molecular geometry is tetrahedral. The expected F-P-H bond angle is 109.50 As the number of lone pairs on central atom increases, the expected bond angle decreases Therefore, the increasing order of bond angle is as follows: FPF FPF Incr easing order of bond angle