Question

PLZ ANSWER QUICKLY! The electronegativity values of carbon, hydrogen, and nitrogen are compared in the table. Comparison of Electronegativity Element Electronegativity Carbon 2.5 Hydrogen 2.1 Nitrogen 3.0 Which of the following statements is true about the strength of the intermolecular forces in CH4 and NH3? (4 points) Select one: a. CH4 ≥ NH3 because CH4 is tetrahedral but NH3 is pyramidal. b. CH4 < NH3 because δ− on C in the CH bond is greater than δ− on N in the NH bond. c. CH4 < NH3 because the NH bond is more polar than the CH bond. d. CH4 ≥ NH3 because CH4 has H bonding but NH3 has dispersion forces.

Answer 1

Answer:

c. CH4 < NH3 because the NH bond is more polar than the CH bond.

Explanation:

Actually, the electronegativity difference between carbon and hydrogen is just about 0.4. This meager difference in electronegativity corresponds to a nonpolar bond between the two atoms.

However, the electronegativity difference between nitrogen and hydrogen is about 0.9. This larger electronegativity difference corresponds to the existence of a polar covalent bond between the two atoms.

Hence the N-H bond is significantly polar unlike the C-H bond. This implies that CH4 molecules are only held together by weak dispersion forces while NH3 molecules are held together by stronger dipole-dipole interactions and hydrogen bonds.