INTRODUCTION
We will observe the action of some elements on the salt solution and will try to assemble them in decreasing order of reactivity series.
BASIC BUILDING CONCEPT
1. The reactivity is made for metals in which higher reactive metal displaces lower reactive metal from its place in a chemical reaction. Reactivity decreases on moving down in the table.
2. Highest reactive metal is at the top, and the lowest reactive metal is at the bottom.
3. The highest reactive metal is potassium, and the lowest reactive metal is gold.
4. Although hydrogen is a non-metal. It also lies in the reactive series.
5. Those metal that lies above hydrogen are more reactive than the hydrogen and can displace hydrogen from their salt solution, while those metal that lies below the hydrogen is less reactive than the hydrogen and can not displace it from their salt solution.
6. Reactivity series is given in the below table.
ELEMENTS SYMBOL
AIM
1. To perform the action of Zn, Fe, Cu, and Al on the given salts solutions:
- ZnSO4 (aq)
- FeSO4 (aq)
- CuSO4 (aq)
- Al2(SO4)3 (aq)
2. Also, assemble these elements (Zn, Fe, Cu and Al) in decreasing order of reactivity.
MATERIAL REQUIRED
1. Test tubes,
2. Test tube stand,
3. Zinc granules,
4. Iron filings,
5. Copper turnings,
6. Aluminium foil,
7. Aqueous solutions of zinc sulphate,
8. Aqueous solution of ferrous sulphate,
9. Aqueous solution of copper sulphate,
10. Aqueous solution of aluminium sulphate.
THEORY
1. Those reactions in which higher reactive metal displaces lower reactive metal from its position are called displacement reactions.
2. It is represented as the equation
A + BX → AX + B
3. If we have three metals A, B and C, C displaces B, and A displaces C, which means C is more reactive than B and A is more reactive than B. If we need to arrange this as decreasing order of reactivity, then A > C> B.
4. The colour of copper sulphate solution is blue, but when we react this salt with zinc, its blue colour changes to reddish-brown colour because zinc is more reactive than copper, it displaces copper from its position.
Zn(s) + CuSO4 (aq)→ ZnSO4 (aq)+ Cu(s)
Zinc Copper Sulphate Zinc Sulphate Copper
Some more examples are;
Zn(s) + FeSO4 (aq)→ ZnSO4 (aq)+ Fe(s)
Zinc Iron Sulphate Zinc Sulphate Iron
Fe(s) + CuSO4 (aq)→ FeSO4 (aq)+ Cu(s)
Iron Copper Sulphate Iron Sulphate Copper
COLOUR OF SOLUTION AND METALS
| NAME | FORMULA | COLOUR |
|---|---|---|
| Aluminium | Al | White |
| Iron | Fe | Blackish grey |
| Copper | Cu | Raddish brown |
| Zinc | Zn | Silvery white (grey0 |
| Aluminium sulphate | Al2(SO4)3 | Colourless |
| Iron sulphate | FeSO4 | Pale green |
| Copper sulphate | CuSO4 | Colourless |
| Zinc sulphate | ZnSO4 | Blue |
PROCEDURE
Step 1: Take four test tubes and take the aqueous solution of ZnSO4, FeSO4, CuSO4, Al2(SO4)3
Step 2: Label them as A, B, C, and D.
Step 3: Add a small strip of aluminium foil into each test tube.
Step 4: Write down your observation.
Step 5: Do the same thing with the remaining salt and observe the changes.
Add iron filling into ZnSO4, FeSO4, CuSO4, Al2(SO4)3.
Add zinc granules into ZnSO4, FeSO4, CuSO4, Al2(SO4)3.
Add copper turnings into ZnSO4, FeSO4, CuSO4, Al2(SO4)3.
OBSERVATION
| S.NO | METAL | SALT | OBSERVATION | INFERENCE |
|---|---|---|---|---|
| Al | Al2(SO4)3 | No change | No displacement | |
| FeSO4 | 2Al(s) +3FeSO4(aq)→Al2(SO4)3(aq) +Fe white Pale green Colourless Blackish grey The colour of salt changes from pale green to colourless. And there will be iron deposits. | Aluminium displaces iron from its solution; therefore, Al is more reactive. | ||
| ZnSO4 | 2Al(s)+3ZnSO4(aq)→Al2(SO4)3(aq)+3Zn Colourless white Colourless Deposits on Al No change in colour is seen. | Aluminium displaces zinc from its solution; therefore, Al is more reactive. | ||
| CuSO4 | 2Al(s) +3CuSO4(aq)→ Al2(SO4)3(aq)+Fe white blue Colourless Reddish brown The blue colour of salt changed to colourless. | Aluminium displaces copper from its solution; therefore, Al is more reactive. | ||
| Fe | Al2(SO4)3 | Fe(s) +Al2(SO4)3(aq)→ No reaction No change is observed. | No displacement | |
| FeSO4 | No change will occur. | No displacement | ||
| ZnSO4 | No change will occur. | No displacement | ||
| CuSO4 | Fe(s) +3CuSO4(aq)→ Fe(SO4)3(aq)+ Cu blue pale green Reddish brown The blue colour of the salt will change into pale green, and the reddish-brown colour will deposit on copper. | Iron displaces copper from its solution; therefore, Fe is more reactive. | ||
| Cu | Al2(SO4)3 | No change will occur. | No displacement | |
| FeSO4 | No change will occur. | No displacement | ||
| ZnSO4 | No change will occur. | No displacement | ||
| CuSO4 | No change will occur. | No displacement | ||
| Zn | Al2(SO4)3 | No change will occur. | No displacement | |
| FeSO4 | Zn(s) + Fe(SO4)(aq)→ Zn(SO4)(aq)+Fe pale green Colourless Blackish grey The pale green colour of the solution change to colourless and blackish-grey iron will form. | Zinc displaces iron from its solution; therefore, Zn is more reactive. | ||
| ZnSO4 | No change will occur. | No displacement | ||
| CuSO4, | Zn(s) + Cu(SO4)(aq)→ Zn(SO4)(aq)+Cu blue Colourless reddish brown The blue of the solution changes to colourless and reddish-brown copper will form. | Zinc displaces copper from its solution; therefore, Zn is more reactive. |
RESULT
1. We have seen aluminium displaces iron, copper and zinc from its solution. So we find Al more reactive.
2. Copper could not displace any metal from its solution; therefore, Cu is the least reactive.
3. Iron could not displace zinc from its solution, but zinc displaced iron from its solution. Therefore zinc is more reactive than iron.
4. If we assemble these metals in decreasing order of reactivity, we find
Al> Zn> Fe> Cu
PRECAUTIONS
1. Handle all the salts and metals with utmost care.
2. Wash your hands properly after the experiment.
3. With the help of sandpaper, clean every metal.
4. Some reactions may take time, so be patient in dealing with them.
CONCLUSION
In this way, we have learned to observe the action of some elements of the reactivity series on the salt solution. We have also assembled them in decreasing order of reactivity.
VIVA QUESTIONS WITH ANSWERS
Q.1 What was the aim of our experiment?
ANS. To observe the action of some elements on the salt solution and try to assemble them in decreasing order of reactivity.
Q.2 What is the increasing order of reactivity of Al, Zn, Cu and iron
ANS. Cu<Fe<Zn<Al
Q.3 Give an equation of the reaction between iron and copper sulphate?
ANS. Fe(s) +3CuSO4(aq)→ Fe(SO4)3(aq)+ Cu
blue pale green Reddish brown
Q.4 Does iron reacts with zinc sulphate?
ANS. No, because iron is less reactive than zinc.
Q.5 Which element is on the top of the reactivity series of metals?
ANS. Potassium
Q.6 Which element is at the bottom of the reactivity series?
ANS. Gold
Q.7 Why there is no reaction between aluminium and aluminium sulphate?
ANS. Because aluminium in aluminium sulphate solution is the same metal.
Q.8 On what property of metal does the reactivity depends?
ANS. The tendency of metals to lose electrons.
Q.9 Which type of reaction is used to describe the reactivity of metals?
ANS. Displacement reaction
Q.10 What if we store AgNO3 in the copper vessel?
ANS. Copper will displace silver from its solution and form CuNO3, forming a hole in the vessel.
Saquib Siddiqui is a Mechanical Engineer and a content creator. He has special interest in science experiments and teaches the same to school and college students. He is also a technical lead at RUDE LABS PVT. LTD.
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