pb2-cu2-and-cd2-can-be-separated-from-other-cations-by-the-addition-of-h2s-based

Question

K_sp PbS = 7.0×10⁻²⁹, K_sp CuS = 8.0×10⁻³⁷, K_sp CdS = 1.0×10⁻²⁸

Accepted Answer

(i) 3.5x10⁻²⁷ M
(ii) 4.0x10⁻³⁵ M
(iii) 5.0x10⁻²⁷ M
All of the Cd²⁺ is still in the solution when Cu²⁺ starts to precipitate.

Answer

(i) 3.5x10⁻²⁷ M
(ii) 4.0x10⁻³⁵ M
(iii) 5.0x10⁻²⁷ M
Half of the Cd²⁺ is still in left the solution when Cu²⁺ starts to precipitate.

Answer

(i) 1.4x10⁻³⁰ M
(ii) 1.6x10⁻³⁸ M
(iii) 2.0x10⁻³⁰ M
Half of the Cd²⁺ is still in left the solution when Cu²⁺ starts to precipitate.

Answer

(i) 1.4x10⁻³⁰ M
(ii) 1.6x10⁻³⁸ M
(iii) 2.0x10⁻³⁰ M
All of the Cd²⁺ is still in the solution when Cu²⁺ starts to precipitate.

Answer

(i) 3.5x10⁻²⁷ M
(ii) 4.0x10⁻³⁵ M
(iii) 5.0x10⁻²⁷ M
None of the Cd²⁺ is left in the solution when Cu²⁺ starts to precipitate.

Answer

(i) 1.4x10⁻³⁰ M
(ii) 1.6x10⁻³⁸ M
(iii) 2.0x10⁻³⁰ M
None of the Cd²⁺ is left in the solution when Cu²⁺ starts to precipitate.