Any compound containing Nitrogen, Oxygen, Fluorine and Chlorine
These elements are highly electronegative because they attract more the bonded electrons, making them have a partially negative charge and the element bonded to it a partially positive charge.
Butan-1-ol is a polar molecule because it has an -OH bond. Oxygen gets a partially negative charge
This is why it can dissolve in water. Hydrogen bonding can occur between the hydrogen of the alcohol and the lone pair of the water molecule.