Which molecule could form a coordinate covalent bond with a proton (h )?

A chlorine (Cl-) molecule could make a coordinated covalent bond with a proton (H +, in this case) forming hydrogen chloride (HCl).

Explanation:

Covalent bonds occur when there is electron sharing between atoms, making all atoms that participate in this type of bond stable, but in the case of coordinated or dative covalent bond, the atom that has available pairs of electrons and is not performing Sharing them with another atom can “donate” these free electrons to any other atom, thereby performing a simple covalent bond and a coordinated or dative covalent bond, where electron (s) transfer from one atom to the other. This type of chemical bond is quite common and often occurs with chlorine, sulfur, phosphorus, among other various chemical elements. As an example we can cite the bond between chlorine and hydrogen to form hydrogen chloride.

For a coordinated covalent bond to occur it is necessary for one of the atoms to share a pair of electrons with another atom, and at the same time assign one or more electrons to another atom, which only participates in the bond receiving the electrons.