When mixing solutions of sodium chloride (NaCl), sodium phosphate (Na₃PO₄), and barium nitrate (Ba(NO₃)₂), one important question arises: Will a precipitate form?
To answer this, we need to consider the nature of the ions involved and their solubility rules. A precipitate forms when an insoluble compound is produced in the solution. Let’s break down the problem:
Step 1: Identify the ions involved
- NaCl dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻).
- Na₃PO₄ dissociates into sodium ions (Na⁺) and phosphate ions (PO₄³⁻).
- Ba(NO₃)₂ dissociates into barium ions (Ba²⁺) and nitrate ions (NO₃⁻).
So, in the reaction, the ions present are:
- Na⁺, Cl⁻, PO₄³⁻, Ba²⁺, and NO₃⁻.
Step 2: Consider possible combinations of ions
For a precipitate to form, two ions in solution must combine to form an insoluble compound. Now, let’s check the possible combinations:
- Ba²⁺ and Cl⁻: Barium chloride (BaCl₂) is highly soluble in water. It will remain dissolved in solution and will not form a precipitate.
- Na⁺ and NO₃⁻: Sodium nitrate (NaNO₃) is also highly soluble in water, so no precipitate will form here either.
- Ba²⁺ and PO₄³⁻: Barium phosphate (Ba₃(PO₄)₂) is insoluble in water. This is a key observation, as when barium ions (Ba²⁺) encounter phosphate ions (PO₄³⁻) in solution, they form a solid precipitate of barium phosphate.
- Na⁺ and PO₄³⁻: Sodium phosphate (Na₃PO₄) is highly soluble in water, so it won’t form a precipitate.
Step 3: Conclusion
Based on the solubility rules and the ions involved, a precipitate will form when barium ions (Ba²⁺) and phosphate ions (PO₄³⁻) combine. The insoluble compound, barium phosphate (Ba₃(PO₄)₂), will precipitate out of the solution.
Thus, when you mix NaCl, Na₃PO₄, and Ba(NO₃)₂ in solution, barium phosphate (Ba₃(PO₄)₂) will be the precipitate that forms.