The observed dipole moment of HCl is 1.08 D and its bond length is 127.5 pm. Taking e=1.6x10^-19 C, 1 D=3.336x10^-30 C m and percent ionic character =100xmu_obs/mu_ionic, find the percent ionic character of the H-Cl bond (nearest integer).

JEE Advanced levelNumerical answerDifficulty 3 of 3cb154

The observed dipole moment of HCl is $1.08 D$ and its bond length is $127.5 pm$ . Taking $e = 1.6 \times 1 0^{- 19} C$ , $1 D = 3.336 \times 1 0^{- 30} C m$ and percent ionic character $= 100 \times μ_{obs} / μ_{ionic}$ , find the percent ionic character of the H-Cl bond (nearest integer).

Numerical answer type, answer in %, tolerance 0.5.

For a purely ionic bond

μ_{ionic} = e d = 1.6 \times 1 0^{- 19} \times 127.5 \times 1 0^{- 12} = 2.04 \times 1 0^{- 29} C m = 6.115 D

. Percent ionic

= 100 \times 1.08/6.115 = 17.66 \approx 18%