Question

A reagent which gives brilliant red precipitate with Nickel ions in basic medium is

• A. sodium nitroprusside
• B. neutral FeCl$_3$
• C. meta-dinitrobenzene
• D. dimethyl glyoxime

Answer 1

The Correct Option is D

To identify the reagent producing a brilliant red precipitate with Nickel ions in a basic medium, each option is evaluated:

1. Sodium nitroprusside: Primarily a test for sulfide ions, it does not react with Nickel ions to yield a red precipitate, particularly in a basic environment.
2. Neutral FeCl₃: Ferric chloride is typically used to test for phenols and does not form a brilliant red precipitate with nickel.
3. Meta-dinitrobenzene: This organic compound does not react with Nickel ions to produce a colored precipitate in any medium.
4. Dimethyl glyoxime: This reagent is known to form a distinctive red precipitate upon complexation with Nickel ions. The reaction is described as follows:

When dimethyl glyoxime is added to a solution containing Nickel ions (\(Ni^{2+}\)) under basic conditions (typically with ammonia or another base), a red precipitate of the nickel(II) dimethylglyoxime complex is generated:

\(Ni^{2+} + 2(C_4H_8N_2O_2) + 2OH^- \rightarrow Ni(C_4H_7N_2O_2)_2 \, (red \, precipitate) + 2H_2O\)

Therefore, dimethyl glyoxime is the correct reagent as it forms a red precipitate with Nickel ions in a basic medium.

In summary, dimethyl glyoxime is the reagent that yields a brilliant red precipitate with Nickel ions in a basic medium.