Question

Giving an example, describe how the formation of coordination compounds is useful in analytical chemistry.

Answer 1

• The formation of coordination compounds plays a vital role in analytical chemistry, particularly in the detection and estimation of metal ions in qualitative and quantitative analysis.
• A classic example is the use of dimethylglyoxime (DMG) in the detection of Ni²⁺ ions.
• When an ammoniacal solution of DMG is added to a solution containing Ni²⁺, a bright red precipitate of a coordination compound is formed:
  \[\ce{Ni^2+ + 2DMG → [Ni(DMG)2]↓}\]
• This red precipitate of [Ni(DMG)₂] is highly characteristic and confirms the presence of nickel.
• It is also insoluble and stable, making it suitable for gravimetric estimation of nickel.