Calculate % ionic character in HCl.
Bond length=1.275∘A, μobserved = 1.03 D
% Ionic character = Observed dipole moment/ theoretical dipole moment ×100 (for 100% ionic bond)
Theoritical dipole moment =4.8 × 10−10 × 1.275 × 10−8 cm=6.12 D=6.12 × 10−18 esu.cm
%IC=(1.036.12) × 100
%IC=0.168 × 100
%IC=16.8%
From dipole moment standard scale,
When a proton (+1) and electron (-1) are separated by distance of 100 pm, the dipole moment in between is 4.8 D.