Question

The pair of species having identical shapes for molecules of
both species is
(a) XeF₂, CO₂ (b) BF₃, PCl₃
(c) PF₅, IF₅ (d) CF₄, SF₄

Answer 1

answer : option (a) XeF₂, CO₂

let's find no of lone pairs and bond pairs of all compounds and then we will define which group has identical shapes for both species.

(a) XeF₂ ⇒no of lone pairs = (7 × 2 + 8 - 2 × 8)/2= 3

and bond pairs = 2

so, linear structure

CO₂ ⇒lone pairs = (6 ×2 + 4 - 8 × 2)/2 = 0

bond pairs = 2 so, linear structure.

both are same.

(b) BF₃⇒ lone pairs = 0 and bond pairs = 3

so, triangular like structure.

PCl₃⇒lone pairs = 1 and bond pairs = 3

pyramidal like structure.

both are different.

(c) PF₅ ⇒lone pairs = 0 and bond pairs = 5

so, triangular bipyramidal

IF₅ ⇒lone pairs = 1 and bond pairs = 5

so, see saw like structure.

both are different.

(d) CF₄ ⇒lone pairs = 0 and bond pairs = 4

so, tetrahedral

SF₄⇒lone pairs = 1 and bond pairs = 4

so, see saw like structure.

both are different.