Why there is no dispersion of light refracted through a rectangular glass slab?

Why there is no dispersion of light refracted through a rectangular glass slab?

Answer:
After refraction at two parallel faces of a glass slab, a ray of light emerges in a direction parallel to the direction of incidence of white light. As rays of all colours emerge in the same direction, i.e., the direction of the incidence of white light, there is no dispersion. However, there is lateral displacement.