Question

Ammonia & water are polar molecules while methane not. Explain.

Answer 1

NH₃, H₂O are polar covalent molecules.
Polar covalent molecules are those molecules which contains polar covalent bond
The bond is said to polar if the electronegativity difference between the bonded atoms is ranging from 0.4 to 1.6
Electronegativity difference in N-H bond (NH₃) = (3.0-2.1) = 0.9
Electronegativity difference in O-H bond (H₂O ) = (3.5-2.1) = 1.4
Hence , NH₃, H₂O are polar covalent molecules
The electronegativity difference ranging from 0.0 to 0.4 it is said to be non polar.
Electronegativity difference in C-H bond (CH₄) = (2.5-2.1) = 0.4
Hence CH₄ is non-polar