question_answer

Dimethyl glyoxime gives a red precipitate with \[2.3\times {{10}^{-2}}{{s}^{-1}}\] which is used for its detection. To get this precipitate readily the best pH range is:

A) \[[{{N}_{2}}{{O}_{5}}]\]                

B)        \[{{[{{N}_{2}}{{O}_{5}}]}_{0}}\] 

C)        \[{{[{{N}_{2}}{{O}_{5}}]}_{t}}\]                 

D)        \[{{N}_{2}}{{O}_{5}}\]

Correct Answer: D

Solution :

Nickel ions \[P{{H}_{3}},As{{H}_{3}},N{{H}_{3}}\] can be best estimated qualitatively and quantitatively by the use of dimethylglyoxine   (DMG)   solution.   The reaction occurs as follows: It may be evidently seen that in this reaction each DMG ion lose one proton. Hence, a basic medium is needed to facilitate this reaction. Thus this reaction is carried out in ammonia cal solution \[l=3\]