Answer
Borax has a higher melting point compared to hexene because the first compound contains boron, an element characterized for forming strong bonds.
Procedure
Borax has a high melting point because it contains boron, which is an element that forms strong covalent bonds with the neighboring atoms. The boron atom is closely packed in its solid state so a large amount of heat is needed to break the bonds between atoms.
Hexene on the other hand is a molecule with a low melting point because the intermolecular forces that hold the bonds together are weak. Additionally, there is not a significant electronegativity difference between carbon and hydrogen, thus, there is not any significant bond polarity resulting in weaker atomic bonding.