1. Unknown Solid Identification
General Chemistry 101/102 Laboratory Manual University of North Carolina at Wilmington

2. Unknown Solid Identification
Purpose
To identify a solid substance based on its physical and chemical properties.
Safety Considerations
Exercise caution when handling the NaOH and HCl solutions. These are fairly concentrated solutions and may cause burns.
Dispose of all liquid wastes in the waste jar in the hood. Place solid wastes in the solid waste container.

3. Unknown Solid Identification
Procedure
Prepare a saturated solution of your unknown. Use this solution whenever a test calls for using the unknown solution.
saturated solution
Test 1: Record the color of your unknown solid and solution.
Test 2: Record the odor of your unknown solid and solution.
nlca/nlcapdf/11NLCAchp9.pdf
Test 3: Add 10 drops of 1 M NaOH to 10 drops of your unknown solution. Gently warm the test tube to check for the odor of ammonia.

4. Unknown Solid Identification
Procedure
Test 4: Test the acid/base properties of your unknown solution with litmus paper.
bases turn red litmus blue
acids turn blue litmus red
Test 5: Clean a wire test loop and conduct a flame test using your solid unknown.
clean wire has only faint yellow flame
use small amount of solid for flame test

5. Unknown Solid Identification
Procedure
Test 5 (cont.): Identify the cation present in the flame test.
Na+ flame test
Ca2+ flame test
Li+ flame test
K+ flame test

6. Unknown Solid Identification
Procedure
Test 6: Add 10 drops of 6M HCl to a small amount of the solid unknown to test for the presence of the carbonate ion.
Test 7: Add 2 drops of 0.1 M AgNO3 to a small amount of the unknown solution in a spot plate to test for the presence of Cl -, Br -, I-, or CO32- ions.
AgCl
AgBr or AgI
Ag2CO3

7. Unknown Solid Identification
Procedure
Test 8: Add 2 drops of 0.1 M Pb(NO3)2 to a small amount of the unknown solution in a spot plate to test for the presence of Cl -, Br -, I-, or CO32- ions.
PbCl2 or PbBr2
PbI2
PbCO3