Insoluble Salt Preparation via Precipitation

Steps:

• Identify method 1 as precipitation, which forms insoluble salts from soluble reactants.
• Select example 2 as lead sulfate, a classic insoluble salt like PbSO₄ from lead nitrate and sodium sulfate.
• Choose collection 3 as filtration to separate the solid precipitate from the solution.
• Determine final step 4 as washing and drying to purify and prepare the salt.

Why C is correct:

• Precipitation produces insoluble salts like lead sulfate (Pb²⁺ + SO₄²⁻ → PbSO₄), collected by filtration and purified by washing/drying, per standard lab procedure.

Why the others are wrong:

• A: Nitrate is soluble, not insoluble; evaporation is for soluble salts.
• B: Evaporation doesn't collect precipitates; filtration is required first.
• D: Titration measures concentrations, not prepares insoluble salts; barium nitrate is soluble.

Final answer: C