Why does CO2 have higher boiling point than CO?
CO2 has more electrons than CO. This means that it has a much larger electron cloud as compared to CO, so its more easily polarised and thus, the ease of forming instataneous dipole-induced dipole bonds increases. Even though CO is a polar molecule and it forms permanent dipole-permanent dipole bonds, in this case the id-id bonds are stronger. 

P.s. Just a 17 year old A Level Chem student here, I might be wrong