Investigating Precipitation Reactions

• Aim
  • To observe the formation of precipitates by mixing solutions of cations and anions and to identify which combinations form insoluble compounds.
• Hypothesis
  • If a cation solution is mixed with an anion solution that forms an insoluble salt, then a visible precipitate will form in the well.
• Risk Assessment

Hazard	Risk	Safety Control Measures
Chemical spills	Skin or eye irritation	Wear safety goggles and gloves
Glassware (droppers, tray)	Breakage and injury	Handle with care
Silver nitrate	Stains skin and clothing	Wash spills immediately, wear lab coat
General chemical exposure	Inhalation or contact	Work in well-ventilated area, no tasting

• Materials
  • Lead nitrate ()
  • Barium chloride ()
  • Silver nitrate ()
  • Copper sulfate ()
  • Potassium iodide ()
  • Sodium sulfate ()
  • Sodium chloride ()
  • Sodium hydroxide ()
  • Sodium carbonate ()
  • Well Tray
• Method
  1. Place a well tray on your bench.
  2. Add two drops of a chosen cation solution to one well.
  3. Add two drops of a chosen anion solution to the same well.
  4. Observe and record whether a precipitate forms.
  5. Repeat for each cation-anion combination.
  6. Record results in the table below.
• Results

Cation / Anion
	Formed Yellow Precipitate	Formed White Precipitate	Formed White Precipitate	Formed White Precipitate	Formed White Precipitate
	No Change	Formed White Precipitate	No Change	No Change	Formed White Precipitate
	Formed Light Yellow Precipitate	Formed White Precipitate	Formed White Precipitate	Formed Yellow Precipitate	Formed Clear White Precipitate
	Formed Yellow Precipitate	No Change	No Change	No Change	Formed Blue Precipitate