Answer:
See explanation
Step-by-step explanation:
Let us consider the two compounds carefully. Carbon dioxide is purely a non-polar molecular compound while the bond between the C2^2- ion and Ca^2+ is ionic thereby making CaC2 an ionic compound.
Recall that ionic compounds have high melting and boiling points due to strong ionic interactions in the structure of the compound.
On the other hand, CO2 is a non-polar substance whose molecules are held together only by weak dispersion forces.
As a result of the reasons outlined above, carbon dioxide has a low boiling point and calcium carbide has a high boiling point.