REACTIONS AND IDENTIFICATION Substance Class Result* 333 (a) Formic acid Acetic acid (b) Oxalic acid (c) Succinic acid (d) Benzoic acid (e) Salicylic acid Lower aliphatic Deep red coloration. Boil acids for one minute and note the formation of a brown ppt. of basic ferric salt. Add dil. HCl: the ppt. dissolves, giving a clear solution. Very faint yellow. Buff-coloured ppt. in the cold. Add dil. H 2 SO 4 : the ppt. dissolves giving clear solution. Aromatic acids Buff-coloured ppt. in the (except phenolic cold. Add dil. H 2 SO 4 : carboxylic acids) the ppt. dissolves, but simultaneously a white ppt. of benzoic acid is produced. Phenolic acid Violet coloration. (Note however that a dilute solution of salicylic acid will give this coloration without any preliminary neutralisation.) (/) Take two test-tubes A and B: in A place about 5 ml. of neutralised tartaric acid solution and in B place 5 ml. of distilled water. To each solution add 3-4 drops of ferric chloride solution. Place a piece of white paper under the tubes, look down their length and
This is the end of the preview. Sign up
access the rest of the document.