Hey there:
density = 11.3 g/cm³
mass = 15,1 g
Therefore:
D = m / V
11.3 = 15.1 / V
V = 15.1 / 11.3
V = 1.336 cm³
The untrue statement is that they high melting points.
The covalent compounds are the compounds exhibiting strong intra-molecular bonds. This is due to the tightness of the atoms within the covalent molecules. The force of attraction between the individual molecules in a covalent compound seems to be weak. The covalent compounds exhibit weak intermolecular forces that hold the atoms together due to this they have a low melting point.
The answer is d
Hope this helps