Question

Find the number of molecules having no $p\pi -d\pi$ bonds:
$P_4{O}_{10},H_2{S}_2{O}_8,H_2{S}_2{O}_7,Xe{O}_3,XeO{F}_4,Xe{O}_2{F}_2,C{H}_4,C{O}_2$

Answer 1

If there is bonding between two atoms where one atom is having one vacant orbital and another is having one lone pair of electrons, then if this electron pair is denoted to vacant $d-$orbital then boding is called $p\pi -d\pi$ bonding.

Carbon does not contain d-orbitals. It does not form $p\pi -d\pi$ bond.