Question

(1 pts) Of the pairs of substances below, which pair involves ion-dipole interactions?

(a) C6H11O6 and CH3OH

(b) KI and LiNO3

(c) C10H8 and C6H6

(d) KBr and H2O

Answer 1

a.

C₆H₁₁O₆ & CH₃OH both are strong covalent compounds => Dipole-dipole interaction force is the dominating force

b.

KI & LiNO₃ both are ionic compounds => ion-ion interaction force dominates

1. KI ---> K⁺ + I^-

2. LiNO₃ ---> Li⁺ + NO₃^-

c.

C₁₀H₈ and C₆H₆ both are non polar compound => dipole-dipole interaction dominates

d.

KBr and H₂O,

1. KBr à K⁺ + Br^- (Ionic compound) & both ions K⁺ & Br^- will induce water olecule forming a dipole => ion-dipole interaction

K⁺ attract oxygen atom of water molecule which carries partial negative charge due dipole formation

K⁺----^--OH₂

Similarly,

Br^- ----- ⁺H---O---H

Br^- attract hydrogen atom of water molecule which carries positive charge.

Ans: D