Lab-Reactions of Fe
Purpose:
-Observe the properties and reactions of the Fe
2+
2+
3+
and Fe
3+
2+
3+
and Fe
Ions
ions
-Determine which ion, Fe or Fe , is present after a chemical reaction
Materials:
0.1 M Fe(NH ) (SO )
3 M HCl
4 2
0.1 M FeCl
4 2
1 M H SO
3
2
4
0.1 M K (Fe(CN) )
3% H O
0.1 M K Fe(CN) )
Mg ribbon
4
3
6
2
6
2
2 test tubes
deionized water
test tube brush
Safety:
-wear goggles
-H SO and HCl are corrosive. Avoid contact with skin and eyes. Wash hands thoroughly before leaving the lab.
2
4
Pre-Lab:
A brand new element, Xx, is discovered and found to have a variable charge of 1+ and 2+. When treated with
chemical A, the source of Xx+ turns green and the source of Xx2+ turns red. Two test tubes are labeled A and B.
Ten drops of the source of Xx+ is placed in test tube A and ten drops of the source of Xx2+ is placed in test tube B.
Both test tubes are sent through a series of reactions with the addition of various reagents. For the final step,
three drops of chemical A is added. Both of the solutions in the test tubes turn red. Determine the before and
after charges of Xx in test tube A and test tube B.
Procedure:
2+
Part A-Reactions of the Fe
1. Place 10 drops of 0.1 M Fe(NH ) (SO ) in 2 different test tubes.
4 2
Ion
4 2
2. To the first test tube, add 2 drops of 0.1 M K (Fe(CN) ). Gently mix the contents in the test tube.
4
6
3. To the second test tube, add 2 drops of 0.1 M K (Fe(CN) ). Gently mix the contents in the test tube.
3
6
4. Dispose of the materials in the test tubes in the appropriate waste container.
5. Clean the test tubes thoroughly and do a final rinse with deionized water to remove any residue.
3+
Part B-Reactions of the Fe
6. Place 10 drops of 0.1 M FeCl in 2 different test tubes.
Ion
3
7. Repeat Steps 2-5 in Part A.
2+
3+
Part C-Treatment of Fe and Fe with HCl and Mg
8. Place 10 drops of 0.1 M Fe(NH ) (SO ) in a test tube.
4 2
4 2
9. Place 10 drops of 0.1 M FeCl in a test tube.
3
10. Add 10 drops of 3 M HCl and a strip of magnesium ribbon to each test tube.
11. Allow the reaction to continue until the strip of magnesium ribbon is completely consumed.
12. When the reaction is complete, add 2 drops of 0.1 M K Fe(CN) ) to each test tube and gently mix.
3
6
13. Repeat Steps 4-5 in Part A.
Part D-Treatment of Fe
2+
3+
and Fe with H SO and H O
14. Repeat steps 8 and 9 in Part C.
15. Add 2 drops of 1 M H SO and 5 drops 3% H O to each test tube
2
4
2
2
16. Gently mix each test tube for approximately 1 minute.
17. Add 2 drops of 0.1 M K (Fe(CN) ) to each test tube and gently mix.
4
18. Repeat Steps 4-5 in Part A.
6
2
4
2
2
Data and Results:
Copy the following tables into your lab book and from your observations, record the color changes that occurred
during the reactions.
Table I-Reactions of the Fe2+ ion
Fe(CN)6
4-
Fe(CN)6
3-
Fe2+
Table II-Reactions of the Fe3+ Ion
Fe(CN)6
4-
Fe(CN)6
3-
Fe3+
Step 1
Step 2
Step 3
Step 4
Testing to determine the charge of the iron ion after chemical treatment
Table III
Iron Ion Treated
Chemical Treatment
Ion Used in Testing
3Fe2+
HCl and Mg
Fe(CN)6
(Part C)
3+
3Fe
HCl and Mg
Fe(CN)6
(Part C)
4Fe2+
H SO and H O
Fe(CN)6
2
4
2 2
(Part D)
4Fe3+
H SO and H O
Fe(CN)
2
4
2
2
Result
6
(Part D)
Conclusion:
2+
3+
4-
1. What is the difference in the reaction of the Fe ion and the Fe ion with the Fe(CN)6 ion?
2+
3+
3-
2. What is the difference in the reaction of the Fe and the Fe ion with the Fe(CN)6 ion?
3. Using Table III, determine the charge of the iron ion before and after the chemical treatment.
a. Step 1
Before
After
b. Step 2
Before
After
c. Step 3
Before
After
d. Step 4
Before
After
4. Why would it be incorrect to name a compound composed of copper ions and chloride ions, copper chloride,
while it would be correct to name a compound composed of calcium ions and chloride ions, calcium chloride?