Consider a solution with an unknown salt. When dilute solutions of Na₂SO₄, NaCl, and Na₂S were added to the solution, all form a precipitate. Identify the cation that the solution contains.

The following results are obtained when an aqueous solution of cation (green spheres) and anion (orange spheres) is mixed: 

Which of the following pairs of cation and anion are consistent with what has been observed? Explain

Cations: K⁺, Cu⁺, Pb²⁺, Co³⁺

Anions: NO₃⁻, Cl⁻, S^2–, AsO₄³⁻

An aqueous solution contains Pb²⁺, Ca²⁺, and K⁺. Identify the reagents that can be used to separate these cations.

Incomplete combustion of natural gases results in the production of CO (g) as the only carbon-containing product. Choose the balanced chemical equation for the incomplete combustion of ethane (C₂H₆).

Order the following reactions according to their types: redox, precipitation, neutralization.

1. NaOH (aq) + HBr (aq) → H₂O (l) + NaBr (aq)

2. MgSO₄ (aq) + Pb(NO₃)₂ (aq)  →  Mg(NO₃)₂ (aq) + PbSO₄ (s)

3. 2 Na (s)   +   Cl₂ (g)   →   2 NaCl (s)