Question

8. Which of the following species have a zero reading for dipole moment? Give brief reasons for your answers, dealing with each species separately. a. BrF3 b. CH2F2 c. CO d. CO2 e. OF2 f. XeF4

Answer 1

(a): BrF3 has a dipole moment of 1.19 D, due to presence of 2 lone pairs and electronegativity difference between Br and F atoms.

(b): CH2F2 has a definite amount of dipole moment, because C atom has no lone pairs. Also the polarity due to two C - F bonds donot cancel each other creating a definite amount of dipole moment.

(c): CO has a dipole moment of 0.122 D due to electronegativity difference between C and O atoms that create polarity in the CO bond.

(d): CO2 has zero dipole moment, because the the polarity of the two C=O bonds are same and in opposite direction. Hence they cancel each other making the total dipole moment equals to 0.

(e): OF2 has also dipole moment because the polarity of the two O-F bond donot cancel each other and hence OF2 has a definite value of dipole moment.

(f): XeF4 has Zero dipole moment. This is due to the symmetrical structure of XeF4, the polarity of the four Xe - F bonds are in opposite direction and they cancel each other. Also the two lone pairs on the Xe atom lie in opposite direction making it non-polar.

Hence among the given compounds only CO2 and XeF4 have Zero dipole moment