A dipole of length $l$ will experience a net torque of magnitude $pE\sin\theta$ when placed in a uniform external electric field and there will be no net force (since the field is uniform).
Also, the torque will tend to align the dipole with the field and bring it to a stable equilibrium.
My question is, if the dipole is in unstable equilibrium, i.e. the angle between $p$ (dipole moment) and the field is 180°, will the torque still tend to align it will the field or not?