How to calculate the & ionic character in H-X bond of Halogen acids.Given that electronegativity of H ,F, Cl, Br. and I are 2.1, 4.0, 3.0, 2.8,and 2.5 respectively.

According to Haney and Smith the percentage of ionic character of a polar covalent bond can be calculated with help of the following expression
The %ionic character of covalent bond is:

 

The % ionic character of H-F bond is

What is" Haney and Smith Scale" and How to use calculation of % ionic character of covalent bond ?

According to Haney and Smith, the percentage of ionic character of a polar covalent bond can be calculated with help of the following expression:
The % ionic character of covalent bond is given as: