Question

The bond length of $HCl$ molecule is $1.275\mathring{A}$ and its dipole moment is $1.03D$. The ionic character of the molecule (in percent) (charge of the electron $=4.8\times 10^{-10}$ esu) is

• A. 100
• B. 67.3
• C. 33.66
• D. 16.83

Answer 1

Answer: (D)

Given,

observed dipole moment $=1.03D$

Bond length of $HCl$ molecule, $d=1.275\mathring{A}$

$=1.275\times 10^{-8}cm$

Charge of electron, $e^{-}=4.8\times 10^{-10}$ esu

Percentage ionic character $=$ ?

Theoretical value of dipole moment $=e\times d$

$=4.8\times 10^{-10}\times 1.275\times 10^{-8}esu-cm$

$=6.12\times 10^{-18}esu-cm$

$=6.12D$

Percentage ionic character

$=\frac{\text{ observed dipole moment }}{\text{ theoretical value of dipole moment }}\times 100$

$=\frac{1.03}{6.12}\times 100$

$=16.83\%$