Tests

• • Flame tests: Used to identify metal ions based on the color of the flame when the substance is heated.
  • Examples include: Lithium (crimson), Sodium (yellow), Potassium (lilac).
• • Precipitation reactions: Used to identify ions that form insoluble salts when two solutions are mixed.
  • Examples include: Silver nitrate with chloride ions to form white silver chloride.
• • Litmus test: Used to determine whether a solution is acidic or alkaline.
  • Red litmus turns blue in alkaline solutions, and blue litmus turns red in acidic solutions.
• • Starch test using iodine: Indicates the presence of starch when iodine turns from brown to blue-black in the presence of starch.
• • Test for reducing sugars with Benedict's solution: Reducing sugars reduce the copper(II) ion from the Benedict's solution to a red-brown copper(I) oxide precipitate when heated.
• • Test for proteins with Biuret reagent: A positive result is indicated by a color change to violet due to peptide bonds reacting with copper ions in the Biuret reagent.
• • Ethanol emulsion test for lipids: When a substance is mixed with ethanol and then water, a cloudy white emulsion indicates the presence of lipids.