####40. The final solution contains
(a) and
(b) and
(c) and
(d) and
Passage 4
-amino-N, N-dimethylaniline is added to a strongly acidic solution of . The resulting solution is treated with a few drops of aqueous solution of to yield blue colouration due to the formation of methylene blue. Treatment of the aqueous solution of with the reagent potassium hexacyanoferrate (II) leads to the formation of an intense blue precipitate. The precipitate dissolves on excess addition of the reagent. Similarly, treatment of the solution of with the solution of potassium hexacyanoferrate (III) leads to a brown colouration due to the formation of .
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Answer:
Correct Answer: 40. (d)
Solution:
- Since, in the beginning, concentrated solution was taken, some remain in solution which gives white precipitate of on addition of . The precipitate finally dissolve in ammonia and present in solution also forms complex with ammonia as
The comprehension describing methylene-blue test.
Blue solution
Therefore,
