1. In this experiment, you can have any of the following ions: Ni 2+, Fe 3+, Al
ID: 1016620 • Letter: 1
Question
1. In this experiment, you can have any of the following ions: Ni 2+, Fe 3+, Al 3+, Zn 2+.
(a) By adding 6 M NaOH in Procedure A, how are these ions separated? For example, what ion(s) are in the supernatant and what ion(s) forms precipitate?
Enter Shift PgDn Alt Ctrl The Experimental Procedure is written for a single reference solution. If you are simul- taneously identifying cations in both a reference solution and a test solution, adjust the procedure accordingly. If the test solution is a sample with an environmental origin, then gravity filter 10-15 mL before beginning the Experimental Procedure. A. Separation of Ni2+ and Fe3+ 11 from Zn2+ and Al Prepare the hot water bath for use in Parts A and ID Separate the hydroxide precipitates from the amphoteric hydroxides. To 2 mL of the reference solution (in a small test tube) add 10 drops of 6 M NaOH (Caution!) (see Dry Lab 4.A). Centrifuge and save the precipitate Test for complete precipita- tion (see Dry Lab 4.B) by adding several drops of 6 M NaOH to the supernatant. Decant the supernatant into a small test tube and save for Part D 11f 1. 13b number of drops of conc HNO3. (Caution: Be careful!) If necessary, heat the solution in the hot water bath for several minutes. 2. Dissolve the hydroxide precipitates. Dissolve the precipitate with a minimumExplanation / Answer
On adding 6 M NaOH, the ions form respective hydroxides: Ni(OH)2, Fe(OH)3, Zn(OH)2, Al(OH)3
Nickel and zinc hydroxides are soluble whereas are iron and aluminium hydroxides are insoluble.in water and form a precipitate. Thus, Ni2+ and Zn2+ will be present in the supertanant liquid whereas Fe3+ and Al3+ will be present as hydroxides in the precipitate.
Iron(III) hydroxide is a reddish-brown precipitate.
Aluminium hydroxide is a gelatinous white precipitate.
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