Question

Trimethylamine oxide and trimethyl phosphine oxide can be represented as :

$(C{H}_3{)}_3\stackrel{+}{N}-O^{-}(C{H}_3{)}_3\stackrel{+}{P}-O^{-}$

(I) (II)

Select the correct structure.

• A. $(C{H}_3{)}_{3}N=O$
• B. $(C{H}_3{)}_{3}P=O$
• C. Both (A) and (B)
• D. None of these

Answer 1

Answer: (B)

$(C{H}_3{)}_{3}P=O$

Due to the absence of vacant d-orbitals, N is unable to expand its valency beyond 4 but P can expand its valency due to the presence of d-orbitals.

The correct structure is - $(C{H}_3{)}_{3}P=O$.

So, option B is correct.