Final answer:
In the reaction 3Na₂S(aq) + 2FeCl₃(aq), the precipitate that forms is iron(II) sulfide (Fe₂S₃), as FeS is insoluble in water according to solubility rules.
Step-by-step explanation:
The student has asked to evaluate the reaction 3Na₂S(aq) + 2FeCl₃(aq) and identify the precipitate that forms. According to solubility rules, the possible products of a double-replacement reaction can be NaCl and FeS. While NaCl is soluble in water, FeS is not and would be the expected precipitate. Thus, when sodium sulfide reacts with iron(III) chloride in aqueous solution, iron(II) sulfide precipitates out of solution. The balanced chemical equation for this reaction would be:
3Na₂S(aq) + 2FeCl₃(aq) → 6NaCl(aq) + Fe₂S₃(s)
→ indicates the direction of the reaction.
According to the solubility rules, the precipitate that forms in the reaction between 3Na₂S(aq) and 2FeCl₃(aq) is FeS. When these two compounds react, the sodium ions (Na⁺) and chloride ions (Cl⁻) combine to form NaCl, which remains soluble. However, the sulfide ions (S²⁻) react with the iron ions (Fe³⁺) to form FeS, which is not soluble and precipitates out of solution.