Bond angle in `PH_(4)^(+)` is higher than that in `PH_(3)`.Why ?

Explanation

`P` in `PH_(3)` in `sp^(3)`- hybridized.It has three bond pairs and one lone pair around `P`. Due to the stronger lone pair-bond pair repulsions than bond pair-bond pair repulsions, the tetrahedral angle decreases from `109^(@)28'` to `93.6^(@)`, As a result, `PH_(3)` is pyramidal. However, when it reacts with a proton, it forms `PH_(4)^(+)` ion which has four bond pairs and no lone pair.Due to the absence of lone pair-bond pair repulsions and presence of four identical bond pair-bond pair interactions, `PH_(4)^(+)` assumes tetrahedral geo-metry with a bond angle of `109^(@)28'`