Answer: its ability to dissolve ionic substances
Explanation: The water molecule contains two hydrogen atoms which are arranged in the bent shape around the oxygen central metal atom.
Due to more electronegativity of oxygen, it has a tendency to attract the electron density of hydrogen, thus itself acquiring the partial negative charrge and there is partial positve charge on both the hydrogen atoms.
This leads to uneven distribution of charge between the hydrogen and oxygen atoms. Due to this, they become ions which are separated by the medium and thus water has also the ability to dissolve the ionic substances in it following the relation of 'Like dissolves Like' .