anions tests

EXPERIMENT TWENTY

Qualitative Analysis of Anions

Analysis of Solutions Containing the Ions
Cl-, Br-, l-, SO42-, CO32-, and NO3-

This experiment continues the qualitative analysis begun in Experiment 19. Here we will be analyzing solutions to determine the presence of anions. The same techniques that were used for the cation analysis must be used for the anions. If you have not carried out Experiment 19, read the introductory section before starting this experiment. The major difference between cation and anion analysis is that in anion analysis, a series of separations of the ions from one another is usually not the most efficient way to determine their presence. Instead, only some separations will be made, and the initial test solution will be used to test many of the ions. Refer to the flow chart at the end of the experimental directions as you proceed.

First you will prepare and analyze a “known” solution which contains all six of the anions. Then you will analyze an “unknown” solution using the same techniques, to determine the presence or absence of each anion.

As in Experiment 19, a description of the physical properties and the chemistry of the substances appears in boxed frames.

Chemicals

Solutions of Anions:

Sodium chloride, NaCl, 0.2 M Sodium bromide, NaBr, 0.2 M Potassium iodide, KI, 0.2 M Sodium sulfate, Na2SO4, 0.2 M

Sodium carbonate, Na2CO3, 0.2 M Sodium nitrate, NaNO3, 0.2 M

Test Reagents:

Silver nitrate, AgNO3, 0.1 M Ammonia, NH3, 6 M Nitric acid, HNO3, 6 M Potassium permanganate, KMnO4, 0.1 M

Mineral oil Sodium hydroxide, NaOH, 6 M

Barium hydroxide, Ba(OH)2, saturated Barium chloride, BaCl2, 0.1 M

Acetic acid, HC2H3O2, 6 M Aluminum(s), granules

Iron(III) nitrate, Fe(NO3)3 0.1 M in nitric acid, HNO3, 0.6 M

To neutralize spills:

Baking soda, NaHCO3(s) Vinegar, HC2H3O2

Equipment

Test tubes, 6, 13- x 100-mm Test tube rack

Wire