Explain, in terms of electronegativity difference, why the bond in a molecule of hf is more polar than the bond in a molecule of hi.

Explanation:

Electronegativity is defined as the ability of an element to attract electrons that link it to another element.

The covalent bond (chemical bond between atoms where electrons are shared, forming a molecule. This bond is established between non-metallic elements) between two atoms can be polar or nonpolar.

When two atoms have different electronegativities, the one with the highest electronegativity will attract the electrons towards each other, generating a separation between the positive and negative charges. In this way a polar bond is produced, the polarity of which will be as the electronegativity difference between the bonded atoms is greater.

In this case you know the following electronegativities:

So the electronegativity differences in the HI and HCl compounds are:

Both compounds have element H that is part of it, only differing in F and I. Since F has greater electronegativity than I, the difference in electronegativity in compound HF will be greater. Then the HF compound will be more polar.