Which of the compounds, c3h8, mgcl2, zn (no3) 2, ocl2, are expected to exist as molecules?

The answer is C3H8 and OCl2 they are molecular compounds. MgCl2 is an ionic compound while Zn (NO3) 2 is an inorganic chemical compound.

Molecular compounds are covalent compounds in which the elements share electrons via covalent bonds. They are inorganic compounds that take the form of discrete molecules, for example water and carbon dioxide.