An organic compound (A) with molecular formula `C_8H_8O` forms an orange precipitate with 2, 4 dinitrophenyl hydrazine and gives yellow precipitate on heating with iodine in presence of sodium hydroxide. It neither reduces Tollen's reagent nor Fehling solution and it also does not decolourise bromine water or Baeyer's reagent. On drastic oxidation with chromic acid it gives a carboxylic acid (B) having molecular formula `C_7H_6O_2`. Identify the compound (A) and (B) and explain in detail the reactions involved