Henry & Smith equation: Calculation of percentage (%) ionic character in covalent compounds?

The percentage ionic character in covalent compound arises due to the electronegative difference of bonding atoms. And percentage ionic character of covalent bond calculates by Henry and Smith equation;

Solved Questions:

(1) The electronegativity of F and H are 4.0 and 2.1 respectively. The percentage ionic character in H and F bond is.

(2) A given compound AB whose electronegative difference is 1.9 . Atomic radius of A and B are 4 and 2 Angstroms the distance between A and B means dA-B is ?

(3) The C–C single bond length is 1.54 Angstroms and that of Cl–Cl is 1.98 Angstroms. If the electronegativity of Cl and C are 3.0 and 2.5 respectively, the C–Cl bond-length will be equal to ?

(4) Stevenson & Schromaker Equation: Determination covalent radius of Heterogeneous Molecules.

(5) How to calculate percentage (%) ionic character in covalent compounds?