Answer:
1. London dispersion
Explanation:
Sulphur trioxide ( SO₃ ) -
The chemical compound SO₃ is planar in structure , the only intermolecular forces shown by SO₃ is the London forces .
dipole - dipole is not observed in this compound , as it is not possible to generate poles between the sulfur and oxygen atom due to very less difference in the electronegativity .
Hydrogen bonding is also not observed , because there is not hydrogen atom .
Hence , only London forces are observed in SO₃ .
