Chapter 2.SE, Problem 33AP

Interpretation Introduction

Interpretation:

Fluoromethane (CH₃F, µ=1.81 D) has a smaller dipole moment than chloromethane (CH₃Cl, µ=1.87 D) even though fluorine is more electronegative than chlorine. This observation is to be explained.

Dipole moment is defined as, µ=Qxr

Where, Q=Magnitude of the charge developed at either end of the dipole.

R=The distance between the charges

It is expressed in Debyes (D). 1 D=3.336x10^-30C.m.

Thus dipole moment values depend not only on the magnitude of charges developed on the dipole but also on the length of the bond.

To explain:

Why fluoromethane (CH₃F, µ=1.81 D) has a smaller dipole moment than chloromethane (CH₃Cl, µ=1.87 D) even though fluorine is more electronegative than chlorine.