Why is it possible for a compound to have more than one bonding? How do you know the type of bond present in compounds? Can you please explain van der Waals, metallic and hydrogen bonding?

It will usually depend on the structure and the current placement of the atoms but it is likely for multiple bonds to form so that different atoms can remain or become stable. There are some compounds that may wreak havoc when they are not stable and this is usually prevented by creating different, multiple bonds.

You will know the type of bond formed based on the elements that are available. When a metal and a non-metal form a bond, this is most likely to be ionic. If the bond is between two nonmetals, this is considered to be covalent.

Van der Waals is considered to be the type of force that may happen between different atoms and molecules. There are forces that may happen even from a distance. Metallic and hydrogen bonds are considered to be highly specialized types of bonds.