Answer to Question #131807 in Inorganic Chemistry for Umair Ahmed Memon

Question

If you are given a metallic sample containing copper than;
How do you estimate the Cu gravimetrically?
What are qualitative measures used to find Cu in a given sample?

Answer 1

Cu is precipitated quantitatively as copper (I) thiocyanate from slightly acid solution in the presence of sulfurous acid using a solution of ammonium thiocyanate as reagent.

2Cu²⁺ + SO₃^2- + H₂O → 2Cu⁺ + SO₄^2- + 2H⁺

Cu⁺ + CNS^- → CuCNS_(pres.)

Qualitative measure will be the formation of CuCNS precipitate.