Concentrate every fraction by distilling off the solvent using a receiver distilling
still fitted with a water-cooled condenser until nearly dry.
Leave each flask to stand till dryness. Weigh each flask with product and calculate
the weight of each product.
Identify the products by determination of their melting points and compare with the
melting points of 2-nitrophenol, 4-nitrophenol and 1,4-benzoquinone, as reported in
the literature.