An orange solid (A) on heating gave a green residuce (B), a colourless gas (C) and water vapour. The dry gas (C) on passing over heated Mg gave a white solid (D). (D) on reaction with water gave a gas (E) which formed dense white fumes with HCl. Identify (A) to (E) and give reactions involved.
Answers
(NH4)2Cr2O7 --> N2 + Cr2O3 + H2ON2 is the colourless gas. Cr2O3 is the green residue. Now N2 gas reacts with magnesium to form a nitride, magnesium nitride. N2 + 3Mg ---> Mg3N2
If we consider that A is a solid that reacts ie gets heated to form B which also forms a green residue like C, Then D is the other compound formed and it reacts with water to form E which will deliver white fumes.
The gas formed in this case is ammonia ie NH3 ie option E answer and answer for option D is Mg3N2 as a compound and the answer for option C is N2 gas.
We can easily obtain N2 from its corresponding compound ie Cr2O7 and it undergoes a change forming Cr2O3 and it can be indicated by the color green. There is a presence of chromium, ion here.
White fumes will be due to HCL.