UPSC Combined Geo-Scientist, Mains · 2026 · Mains Paper I
Q7(a). Separation of Cu and Cd with cyanide and H₂S
Question
An aqueous solution of CuSO₄ and CdSO₄ was combined with excess KCN solution and then H₂S (gas) was passed through the solution mixture to obtain an insoluble yellow-coloured precipitate. Find the products and give reasons, along with equations, as to why only one of the metal compounds is formed as precipitate.
Model answer
The free solution for 2026 answers the questions picked in its time plan. Question 7 is answered in full in the Book Edition of the 2026 solutions of Geo-Scientist Chemistry Paper I.
Coverscyano-complexesSeparation of Cu and Cd with cyanide and H₂S
All parts of Question 7
- 7(a) Separation of Cu and Cd with cyanide and H₂S10 marks
- 7(b) Titration of phenol with NaOH20 marks