Which of the following (A-E) correctly identifies all of the compounds from the list below that contain covalent bonds in their structure?
CO2 (g) Ca(OH)2 (s) H 2SO4 (l) MgCO3 (s) NaCl (s) Na 2O (s) Na 3PO4 (s) SO2 (g) SiO2 (g)

Answer:

14) C

We know that when a metal bonds with a non-metal, an ionic bond is formed. This means that NaCl and Na₂O do not form covalent bonds whilst all other form covalent bonds. So C is correct.