PO(OH)3 - Phosphoric acid - also H3PO4 :

First draw the Lewis dot structure:
H3PO4 Lewis Structure

Electron geometry: tetrahedral. Hybridization: sp3

Then draw the 3D molecular structure using VSEPR rules:

The molecular geometry of PO(OH)3 is tetrahedral with asymmetric charge distribution on the central atom.
Therefore this molecule is polar.

Phosphoric acid on Wikipedia.

Back to Molecular Geometries & Polarity Tutorial: Molecular Geometry & Polarity Tutorial.

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