Question

Which one amongst the following pairs of ions cannot be separated by H₂S in dilute HCl?

(a) Bi³⁺, Sn⁴⁺

(b) Al³⁺, Hg²⁺

(c) Zn²⁺, Cu²⁺

(d) Ni²⁺, Cu²⁺

Answer 1

The correct option (a) Bi³⁺, Sn⁴⁺

Explanation:

(i) Both Bi³⁺ and Sn⁴⁺ (belongs II group) are precipitated by H₂S in presence of dil. HCl.

(ii) Hg²⁺ is precipitated with H₂S in presence of dil. HCl, while Al³⁺ does not.

(iii)Cu²⁺ precipitated with H₂S in presence of dil. HCI while Zn²⁺ does not.

(iv) Similarly Ni²⁺ does not precipitate with H₂S in presence of dil. H₂S, while Cu²⁺ precipitated.