Chemistry - GOC Question with Solution | TestHub
Place the partial charges on the following molecules. Which of the following statements about the partial charges is correct?
(a) 
(b) 
(c) 
(d) 
(e) 
(f) 
(g) 
(h) 
(i) 
Options:
Answer:
Solution:
The electronegative atom pulls electron density toward itself (δ-), and the polarity then alternates along the bonded atoms:
(a) 
(b) 
(c) 
(d) Benzene is nonpolar; it has no localized charges. Its two equivalent resonance forms carry alternating partial charges which cancel:
(e) In toluene, the methyl group carries a formal partial positive charge (hyperconjugation); the ring shows the opposite alternation. (The structure shown is not a hybrid.)
(f) Anisole:
(g) Chlorobenzene:
(h) Nitrobenzene: the polarization is opposite to that in anisole (the nitro group is electron-withdrawing):
(i) Benzoic acid: the same reversed alternation through the ring from the electron-withdrawing carbonyl group:
Answer: (A).
