(a) When the glass plate between the two jars is pulled away then the red brown gas will diffuse from jar A into colourless jar B and vice versa, due to which the red brown colour will spread into jar B.
(b) The phenomenon occurring here is diffusion.
(c) Bromine vapour.
(d) Air.
(e) Potassium permanganate (coloured solid) and water (colourless liquid) also show the same phenomenon.