An orange coloured solution acidified with `H_2SO_4` and treated with a substance `'X'` gives a blue coloured solution of `CrO_5`. The substance `'X'` is

Which of the following gives blue colour with starch solution?

Sodium gives blue colour in NH_(3) solution. This blue colour is due to

Potassium dichromate acts as a strong oxidising agent in the acidic medium. When heated with a metal chloride and conc. sulphuric acid, it gives orange red fumes. On passing these fumes through sodium hydroxide, it gives a yellow solution (X) and this acidified solution gives yellow precipitate (Y) with lead acetate. On heating potassium dichromate with KOH, it forms a yellow solution (Z) which on acidification changes to orange colour. Acidified solution of dichromate ion gives deep blue colour with H_2O_2 due to the formation of (P) The yellow solution (X) is

The reaction between acidified chromic acid solution and H_(2)O_(2) gives a blue colouration due to the formation of -

The yellow colour solution of Na_(2)CrO_(4) changes to orange red on passing CO_(2) gas due to the formation of :-

The yellow colour solution of Na_(2)CrO_(4) changes to orange red on passing CO_(2) gas due to the formation of :-