Question

R LON-CAPA course contents IRLON-CAPACation Test Proc LON-CAPA cation Test EX EY Did Kate Middleton really ru O loncapa nau.edu exp5intro.p problem 0 Humoud Alanjari Student section: K1) CHM 151 Lab Spring 2017 Messages courses Help Logout Main Menu Course Contents st & 5 Pre lab Cation Test procedure Due on Friday, M 3 at 07:30 am (MST Cation Test Procedure In experiment five, the "Identification of lons 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 e used The col or and texture of the precipitate will be important to observe n the entification of the anion the formation of a ga s will be used to hel p ID the anion and a est will be ed to ID the cation in the precipitates W 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 dentification of the cation Final unknown using the same tests done for the known cation solutions nalyze your all o each by obtain each catio ution, then observe while adding 0.5 mL of 1M nd Start ing 1 mL samples Add 0.5 mL of 0.1M sodium carbonate to fresh 1 mL sam es of cations th at di d not form precipitate s with 1M HCl M ammonium hydroxide and mix Test fresh 1 mL samples of cation s th did not form precipitates with Cl by observing while a dding 5 drops of 1M ammoni m hydroxide a nd 1 M Now observe while adding 1 mL 0.15M Na2EDTA to tubes that formed precipitates with 1M ammoni m hydroxide and Add 2mL of 0.15M Na2EDTA to reactions that formed preci pitates with M HCI and mi Incorrect. Tries 15/99 Previous Tries Submit Answe You have entered that answer before 1025 PM a Ask me anything ENG 2/23/2017 R3

Answer 1

The separation of cations starts with acidifying an extract to check for precipitation. The precipitate (if any) is separated and the filtrate is made alkaline to precipitate metal ions of Groups III. If a precipitation occurs, separation, followed by treatment of the filtrate with sodium carbonate gives the ions of Group IV.

The test with EDTA is performed to check for the confirmation of the metal ions.

Therefore, the order is as below:

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

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

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

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

5) Add 0.5 mL of 1 M sodium carbonate to fresh 1 mL samples of cations that did not form precipitates with 1 M HCl or 1 M ammonium hydroxide and mix.

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