Question

Please explain if the following are true or false and how you got your answer.

A. A molecule which contains polar bonds will always have a dipole moment.

B. Valence bond theory explains the bonding in diatomic molecules such as HCl without resortingto the use of hybrid orbitals.

C. In molecular orbital theory, combination of two atomic orbitals produces two molecular orbitals.

D. In applying molecular orbital theory, the bond order is calculated in the same way as with Lewis

structures.

E. In the valence bond treatment, overlap of an s orbital on one atom with an sp3 orbital

on another atom can give rise to a s bond

Answer 1

ANSWER
(A) FALSE: Some molecules have polar bonds but have no dipole moment due to symmetry. For example CCl4 , SO3 etc have polar bonds but net dipole moment of the molecule is zero.

(B) TRUE: Hybridisation is used to explain complex shapes like trigonal planar , tetrahedral etc

(C) TRUE: Two molecular orbitals are produced by overlap of two atomic orbitals. one bonding molecular orbital and other non-bonding molecular orbital.

(D) FALSE: Bond order is the half of difference in bonding and non-bonding electrons. While as in Levs concept there is no concept of bonding and non-bonding electrons.

(E) A sigma bond is formed by the overlap of s-orbital and sp3 hybrid orbital. You have written s bond which is incomprehensible. If it is Sigma bond, it is TRUE.