Question

CO2 is a gas while SiO2 is a solid. Why ?

Answer 1

here is your answer...

CO2 is a gas due to Linear structure but SiO2 is a solid because of it has joit pollymoliric structure.

I hope its help you...

Answer 2

CO2 contains double between carbon and oxygen and this double bond contains strong sigma and pie components. The polarity of this carbon oxygen bond is very low and the attraction force that holds molecule is weak dispersion forces and hence CO2 is a gas.

Now coming to SiO2

It contains only single bond between Silicon and Oxygen. Also SiO2 has a covalent bonded network structure which makes it solid and having high melting point.

Hope it helps.