8.—(1) Crude pyridine must consist of pyridine bases and must not be more deeply coloured than a mixture of 2 millilitres of 0.05 molar iodine with one litre of water.
(2) It must mix readily and completely with alcohol of a strength of not less than 95 per cent alcohol by volume and must give a clear or only slightly opalescent solution when mixed with twice its volume of water.
(3) 10 millilitres of a 1 per cent solution in water must produce immediately a distinct crystalline precipitate on vigorous shaking after the addition of 5 millilitres of an aqueous solution of cadmium chloride containing 5 grammes of the anhydrous fused salt in 100 millilitres, and produce an abundant separation of crystals within 10 minutes.
(4) A white precipitate must be formed when 10 millilitres of a 1 per cent solution in water are mixed with 5 millilitres of Nessler’s reagent.
(5) 1 millilitre of crude pyridine dissolved in 10 millilitres of distilled water must require not less than 9.5 millilitres of 0.5 molar sulphuric acid for neutralisation using screened methyl orange as an indicator.
(6) 100 millilitres distilled in accordance with Determination of distillation characteristics of volatile organic liquids (IP 195/98(2004))(BS 2000-195:1998) must give a distillate of at least 50 millilitres at a temperature of 140°C and of 90 millilitres at 160°C.