The solvent must travel exactly to within one cm of the top of the plate. The azobenzene spots would have migrated farther up the plate. The azobenzene spots would not have migrated as far up the plate. The color of the spots would be slightly altered. No change would have been observed.
Chloroform is a suspected carcinogen.
In TLC the solvent front moves downward. TLC is better for separating volatile compounds. When you processed spinach leaves so that the pigments could be separated by TLC you ground up the leaves in petroleum ether- ethanol. A mixture of three compounds A, B, and C is analyzed by thin-layer chromatography on alumina. After development of the plate and visualization of the components the plate appeared as shown.