Classification is based on feather there is formation of precipitates or not venue metal actions east with the reagent The five groups of actions and the characteristics of these groups are as follows: i. Group I This group actions form precipitate when reacted With HCI ii. Group II Ass*, Bib+, CDC*, cue+, Hag+, Pub*, sin+ This group II actions form precipitate when reacted With HAS in acidic condition.
Iii. Group Ill ca*, r-e*, Zen+, *AAA+, car+ This group Ill actions form precipitate when reacted with HAS in basic condition. Is separated as iv.Group IV ABA*, ca+, MGM+, sir+ This group IV actions form precipitate when reacted with (NH)CHIC.
V. Group V An+, This group V actions form soluble salts when reacted with (NH)CHIC, The Renville to periodicity applied to the results this series to experiments. It helps, in trying to see the periodic pattern, to know the pattern that results when we do a separation and analysis of all metal ions. PROCEDURE Procedure A 1. 2 drops of 6 M HCI was added to 1 ml of the mixture of the metal actions. 2. The suspension was centrifuged for I minute as PPTP.
Of chloride was formed. 3. Additional drop of 6 M HCI was added to the clear supernatant to check for complete precipitation. 4. The supernatant was centrifuged again for I minute as the PPTP.
Was observed again. 5. The supernatant was decanted in a clean test tube. 6. The supernatant was saved for the procedure B. Procedure B I _ MM NH was added drop vise to the solution until basic. 2. The sample was placed in a boiling avatar bath for 2-3 minutes to remove excess NH.
3. The volume Of the solution was adjusted to 2 ml With distilled water and 10 drops of 6 M HCI was added. 4. 12 drops photochemical was added to the solution and stirred. . The sample was heated in a boiling water bath for 10 minutes to allow for the hydrolysis of thickheaded producing HAS.
6. The sample was centrifuged for 2 minutes as the PPTP. Of sulfide was formed. The supernatant was the decanted to a clean test tube. 7. The supernatant was saved for Procedure C. Procedure C 1.
3 additional drops of 1 M thickheaded was added to the supernatant and was reheated for 5 more minutes to test complete precipitation. 2. As the PPTP. Was formed, the supernatant was centrifuged and decanted into a clean test tube and the PPTP. Was discarded 3.
The process to identity sample that only contain single Solution is easier and straightforward, Whereas the detection tot particular ion in a sample that contains several ions is more difficult. This is due to the presence of the large number of ions that interfere tit the test and the difficulty to distinguish between the actions that have similar chemical properties. To solve this problem, systematic separation that involve precipitating and removing of ions is used so that the mixture of actions will only have few The separation of actions depends upon the difference in their tendencies to form precipitates, or to form complex ions.In this experiment, an unknown solution I Vass given in order to identify the metal actions. The metal actions present were predicted by the color of precipitates as well as the solubility of precipitates in excess of the reagent.
The procedure involved in this qualitative analysis only determined the possible group of metal actions. Based on our observation White precipitate was formed When the unknown solution was added with HCI. This indicate that Ace, Hag* and Pub* ion that belong to group actions were present in the solution.These metal ions combine strongly with chloride ion to give insoluble chloride as the metal of qualm scheme group I are soft acids. The ions of Group insoluble chlorides: + CLC [l Where Gag+, Hag+ or Pub+ There are six different Group II actions that formed very insoluble sulfides when they were added with HAS in acidic condition.
However, from the black color of precipitate, it was indicated that only three actions that will probably present in the unknown solution. They are Bib+, Cue* and Hag* ions. Group Ill actions were very difficult to form precipitate than Group II.
However, when the solution was made into basic, the situation changed. The black precipitate was formed to show that Min+, CA+ and F-e; ion were present. The ions of Group II and Ill insoluble sulfides: M+ HAS Z] MS + H+ Where MY Bit, Ouch , High, Min*, CHIC or Fee+ ion The Group IV actions are ABA+, Ca+, and Sir+.
These actions were precipitated s carbonates from a buffered alkaline solution and readily soluble under these conditions. The ions of Group IV form insoluble carbonates: MM+ + COB 2- MUCH Where MM+ = ABA+, ca+, MGM+, or sir+ The Group IV carbonates oeuvre readily soluble in acidic solution.Acetic acid was used instead of a strong acid so that the H+ concentration will not be high enough to prevent the precipitation Of Backer during the nested. Yellow Backer was precipitated upon the addition of Kicker to a buffered slightly acidic solution.
Ledger these conditions, Backer Will precipitate but Carry and Scars will not. Fifth H+ concentration is too high, Backer Will not precipitate. Calcium is precipitated from the remaining buffered solution as the oxalate.
Ca* * CHECK- acacia (yellow) As there were so many probabilities of actions that present in the unknown solution 1, a confirmation test should be done. The purpose of confirmation test is to verify the particular metal action in sequence to distinguish Gag*, Hag* and EBPP ion which all form white precipitate in addiction of 6 M HCI. This test should be done as well as for another group of actions. The precipitate should be washed properly as we determined formation of two layers of precipitate after he supernatant trot Procedure A was added with HAS under acidic condition.