Devise a test to distinguish between Cu2+ and Co2+.
Know how many valence electrons there are in both of them, then make a test to find how many valence electrons in both of them.
Mathtaculator's method is ingenious but extremely difficult to do.
See your post above for [CoCl4]^2-
To devise a test to distinguish between Cu2+ and Co2+, we would need to perform a series of chemical tests that take advantage of the unique properties of these ions. Here is a step-by-step procedure:
1. Prepare a solution containing both Cu2+ and Co2+ ions. This can be done by dissolving copper sulfate (CuSO4) and cobalt chloride (CoCl2) separately in distilled water.
2. Take a small amount of the solution and add sodium hydroxide (NaOH) drop by drop. Cu2+ tends to form a precipitate with hydroxide ions, while Co2+ does not. Observe any color or precipitate formation.
3. If a blue precipitate forms, it indicates the presence of Cu2+. This is due to the formation of copper(II) hydroxide (Cu(OH)2). On the other hand, if no precipitate forms and the solution remains clear, Co2+ is present.
4. To further confirm the presence of Cu2+, add excess NaOH to the remaining solution. If the blue precipitate dissolves, forming a dark blue solution, it confirms the presence of Cu2+.
5. Another way to distinguish between Cu2+ and Co2+ ions is by using a flame test. Take a clean wire loop or a nichrome wire and dip it into the solution. Heat the wire in a flame.
6. If the flame appears green, it indicates the presence of Cu2+, as copper compounds tend to produce a green flame color. If the flame appears pink or blue, it suggests the presence of Co2+.
By performing these tests, we can differentiate between Cu2+ and Co2+ ions based on the observed color changes, precipitate formation, or flame color.