In H2O molecule the oxygen is sp3 −hybridizedand thus, tetrahedral configuration comes into existence. Two positions are occupied by H atoms by forming sigma bonds with two hybrid orbitals and two positions are occupied by lone pairs. The expected bond angle should be109.5∘, but the actual angle is 104.5∘. The lone pair-lone pair repulsions are greater than bond pair-bond pair repulsions. As a result, bond angle in water is reduced from 109.5o to 104.5o.
