Question

In experiment five, the "Identification of Ions in Salts", you will use a series of reactions to identify a cation in one unknown and a cation-anion in another unknown. In this experiment primarily precipitation reactions or dissolving of precipitates will be used. The color and texture of the precipitate will be important to observe. In the identification of the anion the formation of a gas will be used to help ID the anion and a flame test will be used to ID the cation in the anion unknown. Be sure to wear goggles, use the hood when required, dispose of waste properly, and never use cup sinks. You may also want to wear gloves for all or part of this experiment. Start by washing all glassware and rinsing with RO water. Be sure to wash your glassware and rinse with RO water whenever you get a fresh sample of a cation solution and at the end of the experiment. Please put the following experimental steps in the correct order for the identification of the cation.
1 2 3 4 5 6  Add 2mL of 0.15M Na2EDTA to reactions that formed precipitates with 1M HCl and mix well.
1 2 3 4 5 6  Now observe while adding 1 mL 0.15M Na2EDTA to tubes that formed precipitates with 1M ammonium hydroxide and mix well.
1 2 3 4 5 6  Start by obtaining 1 mL samples of each cation solution, then observe while adding 0.5 mL of 1M HCl to each and mix.
1 2 3 4 5 6  Add 0.5 mL of 0.1M sodium carbonate to fresh 1 mL samples of cations that did not form precipitates with 1M HCl or 1M ammonium hydroxide and mix.
1 2 3 4 5 6  Finally analyze your unknown using the same tests done for the known cation solutions.
1 2 3 4 5 6  Test fresh 1 mL samples of cations that did not form precipitates with 1 M HCl by observing while adding 5 drops of 1M ammonium hydroxide and mix.

Answer 1

We will start the test / identification of carions from group 1

Group 1 test:

1) Finally analyze your unknown using the same tests done for the known cation solutions.

2) Start by obtaining 1 mL samples of each cation solution, then observe while adding 0.5 mL of 1M HCl to each and mix. :

There will be formation of ppt of cations of group 1 [AgCl , PbCl2 and Hg2Cl2]

3) Add 2mL of 0.15M Na2EDTA to reactions that formed precipitates with 1M HCl and mix well.

4) Test fresh 1 mL samples of cations that did not form precipitates with 1 M HCl by observing while adding 5 drops of 1M ammonium hydroxide and mix.

5) Now observe while adding 1 mL 0.15M Na2EDTA to tubes that formed precipitates with 1M ammonium hydroxide and mix well.

6) Add 2mL of 0.15M Na2EDTA to reactions that formed precipitates with 1M HCl and mix well.