Question

The bond length of $HCl$ bond is $2.29\times {10}^{-10}m$. The percentage ionic character of $HCl$, if measured dipole moment is $6.226\times {10}^{-30}C-m$, is:

• A. 8%
• B. 20%
• C. 17%
• D. 50%

Answer 1

Answer: (C)

17%

The percentage ionic character is observed dipole moment divided by calculated dipole moment × 100

The calculated dipole moment (calculated assuming one electron has been completely transferred from hydrogen to bromine) is dependent on the bond length (interatomic spacing), not the radius.

The calculated dipole moment is charge on electron×radius of molecule

$=1.6\times {10}^{-19}\times 2.29\times {10}^{-10}$.

Percentage of ionic character is $[6.226\times {10}^{-19}/3.664\times {10}^{-20}]\times 100$ $=16.9$%