by the gradual oxidation of indigo, a substance is formed which crystallizes in large red prisms, and is termed ISATINE.
If the process be more violently carried on, the constitution of the indigo is broken up, and a new type formed, thus: by the action of an excess of nitric acid on indigo, two remarkable bodies are formed, the ANILIC and the PICRIC acids .....
benzaldehyde is not 'formed' from the oxidation of indigo - it is an intermediate in the preparation of certain aniline dyes, eg indigo.
the crossword setter is no chemist .....
Montcrieff -
it is normal custom on this site to give the number of letters for the answer, and to post your questions together, not separately one by one (knocks other questions off the front page)