Question

Increasing order of dipole moment is-

• A. CF₄ < NH₃< NF₃< H₂O
• B. CF₄ < NH₃< H₂O < NF₃
• C. CF₄ < NF₃< H₂O < NH₃
• D. CF₄ < NF₃< NH₃< H₂O

Answer 1

Answer: (D)

CF₄ < NF₃< NH₃< H₂O

Answer 2

CF₄ is symmetrical and non-polar , hence µ = 0. In NF₃ , the resultant of three N–F dipoles oppose the effect of lone pairs of electrons of N-atom whereas in NH₃, the effect of lone pairs of electrons of N atom and resultant of three N–H dipole are in the same direction. Therefore $µ_{NH_{3}}$ (= 1.46 D) > $µ_{NF_{3}}$

$µ_{H_{2}O}$ = 1.85 D.