Explanation:

Given:
- Dipole moment of diatomic molecule AB = 1.6 D
- Internuclear distance = 100 pm

Dipole Moment:
The dipole moment of a molecule is a measure of the separation of positive and negative charges within the molecule. It is represented by the symbol "μ" and is measured in Debye (D).

Percentage of Electronic Charge:
To determine the percentage of electronic charge existing on the more electronegative atom in the diatomic molecule AB, we need to consider the concept of electronegativity.

Electronegativity:
Electronegativity is a measure of the tendency of an atom to attract electrons towards itself in a chemical bond. It is a relative scale, with the most electronegative element (fluorine) assigned a value of 4.0. The electronegativity difference between two atoms in a molecule determines the polarity of the bond.

Calculation:
In a diatomic molecule, the dipole moment (μ) is given by the product of the charge (q) and the distance of separation (d) between the charges.
μ = q * d

The dipole moment can also be expressed in terms of the bond length (r) and the percentage of electronic charge (x) on the more electronegative atom.
μ = x * e * r
where e is the electronic charge.

Comparing the two equations, we can equate q * d with x * e * r.
q * d = x * e * r

Rearranging the equation, we can solve for x (the percentage of electronic charge).
x = (q * d) / (e * r)

Substituting the given values:
q = 1.6 D (dipole moment)
d = 100 pm (internuclear distance)
e = electronic charge = 1.6 x 10^-19 C (Coulombs)
r = 100 pm = 100 x 10^-12 m

Converting pm to meters:
r = 100 x 10^-12 m = 1 x 10^-10 m

Substituting the values:
x = (1.6 D * 1 x 10^-10 m) / (1.6 x 10^-19 C * 1 x 10^-10 m)
x = 10%

Therefore, the percentage of electronic charge existing on the more electronegative atom in the diatomic molecule AB is 10%.

Answer: d) 10%