Respuesta :

Dejanras
For this you will need electronegativity(χ).  χ(Ca)=1, χ(Cl)=3, χ(Fe)=1,8, χ(O)=3,5, χ(H)=2,1, χ(S)=2,5, χ(F)=4. then you calculate difference of electronegativity between 2 atoms, where is highest, that is higly polar bond. So it is Ca-O bond Δχ=2.