Question

Arrange the following in order of increasing;

(A) Dipole moment of H₂O, H₂S , BF₃ 

(B) Covalent character of LiCl, LiBr , LiI 

(C) Covalent character of NaCl , MgCl₂ , AlCl₃

Answer 1

(A) BF₃ is a symmetrical molecule. It has zero dipole moment. Oxygen being more electronegative than S, bond moment of O-H is more than S-H. So the dipole moment are in the order of BF₃<H₂S<H₂O.

(B) The anion size in increasing order is Cl^-<Br^-<I^-. Hence LiCl is least covalent than LiI . The order is LiCl<LiBr<LiI.

(C) Cation size in decreasing order is Na⁺ >Mg²⁺ >Al³⁺. Thus Al³⁺ ion has maximum polarization effect and Na⁺ ion has least. Thus the covalent order is NaCl <MgCl₂<AlCl₃