Question

If AB₄ molecule is a polar molecule, a possible geometry of AB₄ is :

(1) Square pyramidal 

(2) Tetrahedral 

(3) Square planar 

(4) Rectangular planar

Answer 1

Correct option is (1) Square pyramidal

If AB₄ molecule is a polar molecule, a possible geometry of AB₄ is Square pyramidal.

For AB₄ molecule the possible geometry are:

S. No.	Geometry	H.O	b.p	1.p	Nature of molecule
1	Tetrahedral	sp3	4	0	Non-polar
2	Rectangular planar	sp3d	4	1	Non-polar
3	Square planar	sp3d2	4	2	Non-polar

Square pyramidal is polar because the structure is

The dipole moment of A is never cancelled by others.

Answer 2

Answer is (1) Square pyramidal

(1) If AB 4 molecule is a square pyramidal then it has one lone pair and their structure should be

and it should be polar because dipole moment of lone pair of 'A' never be cancelled by others.

(2) If AB₄ molecule is a tetrahedral then it has no lone pair and their structure should be

and it should be non polar due to perfect symmetry.

(3) If AB₄ molecule is a square planar then

it should be non polar because vector sum of dipole moment is zero.

(4) If AB₄ molecule is a rectangular planer then

it should be non polar because vector sum of dipole moment is zero.

Answer 3

square pyramidal