NTA Abhyas NEET2020ChemistryGeneral Principles and Processes of Isolation of MetalsPractice
The electrolytes usually used in the electroplating of gold and silver, respectively, are
Options
- A[ A u ( O H ) 4 ] - and [ A g ( O H ) 2 ] -
- B[ A u ( C N ) 2 ] - and [ A g C l 2 ] -
- C[ A u ( N H 3 ) 2 ] + and [ A g ( C N ) 2 ] -
- D[ A u ( C N ) 2 ] - and [ A g ( C N ) 2 ] -
Correct answer
D. [ A u ( C N ) 2 ] - and [ A g ( C N ) 2 ] -
Step-by-step solution
Amine complexes of gold are not stable, so, they cannot be used as a solvent.Moreover, in electroplating with silver, silver cyanide is used as electrolyte because the cyanide ion, C N - , reacts with silver ion, A g + to form the complex ion A g ( C N ) 2 - . This produces a silver and more adherent silver plating.