Question

1. For HF and HBr, the partial positive charge on H atom is 0.29 and 0.09, respectively. Use electronegativities (EN) to explain why the partial charge on H in HF is more positive than the partial charge on H in HBr.

Answer 1

Answer:

Electro negativity decreases down the group

Explanation:

One of the known periodic trends is that electro negativity decreases down the group but increases across the period. The electro negativity of fluorine is 3.98 on the Pauling's scale while that of bromine is 2.96. Hence the magnitude of charge separation and degree of partial positive charge on hydrogen in HF must be much greater than that of HBr to a large extent due to the significant difference in electronegativity in HF compared to HBr.