Question

explain in terms of electronegativity difference Y the bond between hydrogen and oxygen in a water molecule is more polar than the bond between hydrogen and nitrogen in an ammonia molecule

Answer 1

Answer: More the electronegativity difference, more polar will be the bond.

Explanation: The electronegativity is defined as the tendency of an element to attract a shared pair of electron towards itself in a chemical bond.

Polarity of the bond is described by the electronegativity difference between the elements making the bond. More the electronegativity difference, more polar is the bond.

The electronegativities of oxygen, hydrogen and nitrogen are:

For Oxygen : 3.44

For Hydrogen : 2.1

For Nitrogen : 3.04

In $H_2O$

Electronegativity difference between oxygen and hydrogen = (3.44 - 2.1) = 1.34

In $NH_3$

Electronegativity difference between nitrogen and hydrogen = (3.04 - 2.1) = 0.94

As, the Electronegativity difference between oxygen and hydrogen is more, therefore water molecule is more polar.