A yellow precipitate is obtained when:

When a white crystalline compound X is heated with K_2Cr_2O_7 and concentrated H_2SO_4 a reddish-brown gas A is evolved. On passing A into caustic soda solution, a yellow-coloured solution B is obtained neutralising the of lead acetate, a yellow precipitate C is obtained. When X is heated with NaOH solution a colourless gas is evolved and on passing this gas into K_2HgI_4 solution a reddish-brown precipitate D is formed. Identify A,B,C,D, and X. Write the equations of the reactions involved.

When a white crystalline compound X is heated with K_(2)Cr_(2)O_(7) and concentrated H_(2)SO_(4) a reddish brown gas A is evolved. On passing A into caustic soda solution, a yellow coloured solution of B is obtained. Neutralizing the solution B with acetic acid and on subsequent addition of lead acetate, a yellow precipitate C is obtained. When X is heated with NaOH solution, a colourless gas is evolved and on passing this gas into K_2HgI_4 solution, a reddish brown precipitate D is formed. Identify A, B, C, D and X. Write the equations of reactions involved.

Identify D When a white crystalline compound X is heated with K_2Cr_2O_7 and concentrated H_2SO_4 , a reddish brown gas A is evolved. On passing A into caustic soda solution a yellow coloured solution of B is obtained Neutralising the solution of B with acetic acid and on subsequent addition of lead acetate, a yellow precipitate C is obtained. When X is heated with NaOH solution a colourless gas is evolved and on passing this gas into K_2Hgl_4 solution a reddish brown precipitate D is formed.

When a white crystalline compound 'X' is heated with K_(2)Cr_(2)O_(7) and concentrated H_(2)SO_(4) a red dish brown gas 'A' is evolved. On passing 'A' into caustic soda solution, a yellow coloured solution of 'B' is obtained. Neutralising the solution 'B' with acetic acid and on subsequent addition of lead acetate a yellow precipitate C is obtained. When 'X' is heated with NaOH a colourless gas is evolved and on passing this a gas into K_(2)HgI_(4) (Nessler's reagent) solution a reddish brown precipitate D is formed. Identify '(A), (B), (C), (D) and X. Write equations for the reactions involved.

If silver nitrate solution is added to a salt solution and a yellow precipitate is obtained the salt may contain