Question

Which of the following is most stable ?

• A.
  
  Structure(A)
• B.
  
  Structure (B)
• C.
  
  Structure(C)
• D.
  
  Structure(D)

Answer 1

Answer: (A)

In (C) and (D) there is $lp-bp$ repulsions. The size of methyl group is greater than $F$ , hence (B) experience greater repulsion than (A).

according to bent rule more electronegative atom occupy axial position because axial position has more p- character, so 2 F atoms placed at axial first then rest of F atom occupy equatorial position.