Statement (a) : ${\mathrm{CO}}_2$ has no dipole moment, whereas ${\mathrm{SO}}_2$ and ${\mathrm{H}}_2\mathrm{O}$ have dipole moment 

Statement (b) : ${\mathrm{SnCl}}_2$is ionic, whereas ${\mathrm{SnCl}}_4$ is covalent.
Which of the following is correct?

(a) ${\mathrm{CO}}_2$ has linear structure while ${\mathrm{SO}}_2$and ${\mathrm{H}}_2\mathrm{O}$ have V-shaped structures. Hence, dipole moment in ${\mathrm{CO}}_2$ is cancelled out but ${\mathrm{SO}}_2$ and ${\mathrm{H}}_2\mathrm{O}$ posses a dipole moment.

(b) Low charge on the cation favors the formation of Ionic bond. Hence SnCl₂(Sn⁺²) is Ionic and SnCl₄(Sn⁺⁴) is covalent.

 Tin (II) chloride ionic or covalent? In SnCl₂, Sn has +2 oxidation state. In accordance to Fajan's rule, the central metal with more oxidation number will be to be more covalent. Therefore, ${\mathrm{SnCl}}_4$ is more covalent than ${\mathrm{SnCl}}_2.$