is 1,3-dibromo prop-1,2-diene optically active or not? please answer

It`s not optically active. It is a planar structure and has a cut through plane of symmetry. Draw the structure. You will see the plane of symmetry clear enough. If you still have doubts, do ask.

It is optically active as it is cummelene which has 2 double bonds.. Here the carbon atom at the the centre looses it`s coplanarity an comes out of page.. ie the molecule is not coplanar so it is chiral and shows optical isomerism... Remember when cummelene have even double bonds then they are optically active and if they have odd double bonds then they show geometrical isomerism if they have different groups at carbon... Hope U like it.. Ask if any further queries