The dipole moment of water is 1.84D and dipole moment of O-H bond is 1.5D. Calculate the H-O-H bond angle in water.

Explanation

Net dipole moment of a molecule, `mu = (m_1^2 + m_2^2 + 2m_1m_2 cos theta)^(1//2)`
Substituting the values of `m_1, m_2 and mu` in the relation : `1.84 = [ (1.5)^2 + (1.5)^2 + 2 xx 1.5 xx 1.5 cos theta]^(1//2)`
Squaring both sides, `3.3856 = 2.25 + 2.25 + 4.5 cos theta , cos theta = -0.2476 rArr theta = cos (-0.2476) = 104.3^@`