Which of the following solids has the highest melting point?(1) H2O(s) (3) SO2(s)(2) Na2O(s) (4) CO2(s)
The answer is (2) Na2O. Considering these compounds status under room temperature. H2O is liquid. CO2 and SO2 are gas. Na2O is solid. So the Na2O has the highest melting point.