Answer:
Due to difference in the values of electronegativities.
Explanation:
A covalent bond is formed between hydrogen atom with a partial positive charge on it and another atom, such as oxygen, have a partial negative charge on an adjacent molecule. This is because of the difference in the values of electronegativities. The hydrogen atom has lower electronegativity value as compared to oxygen so the shared pair of electron is slightly attracted by oxygen atom towards itself and formed partial positive charge on hydrogen and partial negative charge on oxygen atom.
