A complex having molecular formula `Cr(NH_3)_4CI_2Br` has two isomers `'A'` and `'B'`. The isomer `'A'` given a white precipitate with `AgNO_3` solution, while `'B'` gives a yellow precipitate. Identify A and B.

An organic compound (P) having molecular formula C_(9)H_(10)O form an orange precipitate (Q) with 2,4-DNP reagent. Compound (P) gives a yellow precipitate (R ) when heated in the presence of iodine and NaOH along with a colourless compound (S). (P) neither reduce Tollen's reagent or Fehling's solution nor it decolourises bromine water. On drastic oxidation of (P) with chromic acid, a carboxylic acid (T) having molecular formula C_(7)H_(6)O_(2) is obtained. Deduce the structures of the compounds (P) to (T).