$\text{Electric Field due to dipole at (r,0) is } E = \frac{p}{4\pi \epsilon_0 r^3}$

$F = qE = q\frac{p}{4\pi \epsilon_0 r^3}$

$ \text{Work done by Electric Field is } W = qE.2r = \frac{qp}{2\pi \epsilon_0 r^2}$