CBSE Chemistry Experiment Reactivity Series Experiment

Chemistry Experiment - Reactivity Series Experiment

Reactivity series is a group of metals arranged from highest to lowest reactivity. As a result, the term "metal reactivity series" refers to a group of metals arranged in ascending order of reactivity. It also goes by the name "activity series." Metals' reactivity is caused by either their electronic structure or by the incompleteness of their outer orbitals. As they tend to lose electrons, metals produce positively charged ions. High atomic number metals are more likely to be reactive since their electrons can be withdrawn with ease because the distance between the positively charged nucleus and the electron in the valence shell is huge.

Table of content

• Aim

• The action of Zn, Fe, Cu, and Al metals with ZnSO4 

• The action of Zn, Fe, Cu, and Al metals with FeSO4 

• The action of Zn, Fe, Cu, and Al metals with CuSO4 

• The action of Zn, Fe, Cu, and Al metals with Al2(SO4)3 

• Result

Aim

To see how the following salt solutions are affected by Zn, Fe, Cu, and Al metals:

• ZnSO4 

• FeSO4 

• CuSO4 

• Al2(SO4)3 

Materials Required

1. Test tubes

2. Test tube stand 

3. Zn granules 

4. Fe filings 

5. Cu turnings Al foil 

6. Aqueous solutions of zinc sulphate

7. Aqueous ferrous sulphate

8. Aqueous copper sulphate 

9. Aqueous aluminium sulphate.

Theory

1. In a displacement reaction, an ion or an atom from the zinc sulphate element replaces an ion or an atom from the molecule. It could be indicated as 

X + YZ → XZ + Y

2. Based on the reactivity series, displacement reactions occur when a more reactive metal displaces a less reactive metal from its salt solution.

3. If metal A substitutes metal B in its aqueous solution, then metal A is more reactive than metal B for the three different metals A, B, and C.

4. The increasing sequence of reactivity is as follows, if metal C displaces metal B from its salt solution but metal A displaces metal C from its salt solution:

B < C < A

5. The blue colour of copper sulphate begins to fade when Zn bits are dipped in it, and reddish brown copper particles fall to the bottom. This happens due to the following reaction, 

Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)

6. It means that zinc has displaced copper from copper sulphate solution, i.e. zinc is more reactive than copper.

The action of Zn, Fe, Cu, and Al metals with ZnSO4 

1. Al can displace Zinc from their salt solution, therefore it is more reactive than Zn.

2. Whereas Fe and Cu cannot displace Zinc from their salt solution, therefore it is less reactive than Zn.

1. Zn(s)  +  ZnSO4(aq) → No reaction

2. Fe(s)  +  ZnSO4 (aq) → No reaction

3. Cu(s)  +  ZnSO4 (aq) → No reaction

4. 2Al(s)  +  3ZnSO4(aq) → Al2(SO4)3  + 3Zn (s)

The action of Zn, Fe, Cu, and Al metals with FeSO4 

1. Zn and Al can displace Fe from their salt solution, therefore it is more reactive than Fe.

2. Whereas Cu cannot displace Fe from their salt solution, therefore it is less reactive than Zn

1. Zn(s)  +   FeSO4(aq) → ZnSO4(aq)  +  Fe(s)

2. Fe(s)  +   FeSO4 (aq) → No reaction

3. Cu(s)  +   FeSO4(aq) → No reaction

4. 2Al(s) +  3 FeSO4(aq) → Al2(SO4)3  +  3Fe(s)

The action of Zn, Fe, Cu, and Al metals with CuSO4 

1. Zn, Fe, and Al can displace Cu from their salt solution, therefore they all are more reactive than Cu.

1. Zn(s)  +  CuSO4(aq) → ZnSO4(aq)  +  Cu(s)

2. Fe(s)  +  CuSO4 (aq) → FeSO4(aq)  +  Cu(s)

3. Cu(s)  +   CuSO4(aq) → No reaction

4. 2Al(s) +  3CuSO4(aq) → Al2(SO4)3  +  3Cu(s)

The action of Zn, Fe, Cu, and Al metals with Al2(SO4)3

1. Zn, Fe, and Cu can not displace Al from their salt solution, therefore they all are less reactive than Al.

1. Zn(s)  +  Al2(SO4)3(aq) → No reaction

2. Fe(s)  +  Al2(SO4)3(aq) → No reaction

3. Cu(s)  +   Al2(SO4)3(aq) → No reaction

4. 2Al(s) +  Al2(SO4)3(aq) → No reaction

From this, it can be concluded that aluminium is the most reactive and copper is the least reactive among the given four metals (Fe, Zn, Cu, and Al). Thus, the decreasing order of reactivity of metals is

Al > Zn > Fe > Cu

Procedure

1. Prepare 50 ml solutions of 5% concentration (by volume) of zinc sulphate, iron (II) sulphate, copper (II) sulphate and aluminium sulphate in distilled water in four different beakers.

2. In each test tube, place approximately 10 mL of saturated solutions of zinc sulphate (ZnSO4), ferrous sulphate (FeSO4), copper sulphate (CuSO4), and aluminium sulphate (Al2(SO4)3). Take note of the solution's colour.

3. Metal strips made of zinc, copper, iron, and aluminium should be thoroughly cleaned.

4. Place a zinc metal strip in each of the four test tubes (A, B, C, and D) and watch what happens.

5. By dipping additional metal strips in new salt solutions of metal and watching for displacement reactions, repeat the experiment described above with additional metal strips.

Observation

Result

1. From the reactivity series experiment, the action of metals on respective salt solutions are given below:-

1. Al metal is the most reactive because it can remove Zn, Fe, and Cu from salt solutions.

2. Zn metal is more reactive than Fe and Cu because it can remove Fe and Cu from their salt solutions.

3. Fe metal is more reactive than copper because it may remove Cu from its salt solution.

4. Cu is the least reactive metal since it cannot remove any metal (among Al, Fe, and Zn) from its salt solutions.

2. The decreasing order of metal reactivity on the basis of experiment, based on the above results, follows the order:
   Al > Zn > Fe > Cu

Precautions

1. The equipment should be dry and clean.

2. Take care when handling the chemicals.

3. So pay close attention to the changes as some reactions could happen gradually.

4. Never taste or touch the chemicals.

5. Before dipping the metals in the salt solutions, clean them by rubbing them with sandpaper.

6. After each set of observations of how a specific metal interacts with the four salt solutions, clean the test tubes.

7. Use only purified water and a minimal amount of sulphuric acid to create solutions.

8. After the experiment, wash your hands thoroughly because the salt solutions are harmful.

Lab Manual Questions

1. What do you notice when copper is added to a solution of iron (II) sulphate?

Ans. Because copper is less reactive than iron, there is no reaction when copper is introduced to an iron (II) sulphate solution.

2. Which metal in the aforementioned experiment is the most and the least reactive?

Ans. Aluminium is the most reactive metal in the experiment shown above, whereas copper is the least reactive.

3. Why is it safe to preserve iron (II) Sulphate in a copper vessel, whereas the same cannot be safely preserved in a Zinc vessel?

Ans. Since copper is less reactive than iron, iron (II) sulphate can be safely stored in a copper vessel. However, because zinc is more reactive than iron, it cannot be used to safely store iron (II) sulphate.

4. When an aluminium strip is kept immersed in freshly prepared ferrous sulphate solution taken in a test tube, what change would you observe?

Ans. The displacement process causes the solution's light green colour to fade to colourlessness.

Viva Questions

1. Why does the reactivity of various metals vary?

Ans. Each metal has a unique ability to lose electrons, and as a result, each metal has a unique level of reactivity.

2. What does the metal reactivity series show?

Ans. According to the reactivity series, metals are grouped according to decreasing levels of reactivity.

3. Name the reaction, used to compare the reactivities of various metals.

Ans. Displacement reaction is used to compare the reactivities of various metals.

4. Name three metals which occur in free state.

Ans. The metals that occur in free state are:- Gold, Silver, and Platinum.

5. Which of the following metals would allow a dilute solution of HCl to release H2 gas? Zn, Ag, and Hg Why?

Ans. Zn would be able to displace hydrogen from dil. HCl solution and H2 gas is obtained, as Zn is more reactive than hydrogen. On the other hand, Ag and Hg being less reactive than hydrogen do not liberate H2 gas from dil. HCl solution.

6. Why are silver and gold used to make ornaments?

Ans. Silver and Gold are used to make ornaments as they are not tarnished by air and moisture because they are less reactive.

7. It has been noted that when Zn particles are added to a CuSO4 solution, the blue colour fades. Why?

Ans. Zn is more reactive than Cu, therefore it removes Cu from the CuSO4 solution and forms the colourless ZnSO4. This chemical change causes the blue solution to become colourless.

8. What occurs when a Cu wire is immersed into a FeSO4 solution? Why?

Ans. No reaction occurs, as Cu is less reactive than Fe, so it does not displace Fe from its salt solution.

9. Can AgNO3 be kept in a Cu vessel?

Ans. The answer is no. Because Cu is more reactive than Ag, storing AgNO3 in a Cu vessel will cause holes to appear in the Cu vessel and Ag to be displaced from its salt solution.

10. What do you mean by salt?

Ans. A salt is an ionic molecule that has an anion (-ve ion) other than OH- and a cation ( + ve ion) other than H + .

Practical Questions

1. Determine which of the following two chemicals produces coloured solutions.

a. Al2(SO4)3, FeSO4

b. FeSO4, CuSO4

c. CaCl2, ZnSO4

d. ZnSO4, CuSO4

Ans. FeSO4, CuSO4 is the pair of compounds, that will form coloured solutions

2. Determine the most and least reactive elements based on the order of reactions:

A + BX → AX + B

C + AY → CY + A

a. A, C

b. B, C

c. C, A

d. C, B

Ans. C, B are the most and least reactive elements, respectively. Based on the order of reactions.

3. To a copper sulphate solution, iron filings were added. After 10 minutes, it was noticed that the solution's original blue colour had changed and that a coating had formed on the iron filings. The colour of the solution and that of the coating would respectively be

a. Yellow and green

b. Brown and blue

c. Red and greenish-blue

d. Green and reddish-brown

Ans. The colour of the solution will become green and the colour of the coating would be reddish-brown because a more reactive metal (Fe) displaces the least reactive metal from it solution (CuSO4)

4. In an experiment, solutions of ZnSO4, CuSO4, Al2(SO4)3, and FeSO4 are used to react with individual metals Al, Zn, Cu, and Fe. The results are summarised as follows, where "✓" denotes that the reaction occurs and ‘✖’ means no reaction occurs.

On the basis of the above result, the order of the reactivity of the metals may be concluded as

a. Al > Zn > Fe > Cu

b. Zn > Al > Fe > Cu

c. Al > Fe > Zn > Cu

d.  Zn > Fe > Al > Cu

Ans. The order of the reactivity of the metals may be concluded as Al > Zn > Fe > Cu.

5. When a strip of zinc metal is put in copper sulphate solution, the ________ colour of copper sulphate fades gradually.

a. Black

b. Blue

c. Red

d. Green

Ans. When a strip of zinc metal is put in copper sulphate solution, the blue colour of copper sulphate fades gradually.

6. Which of the following pairs will give a displacement reaction?

a. FeSO4 and Copper metal

b. FeSO4 and Aluminium metal 

c. Al2(SO4)3 and Gold metal 

d. ZnSO4 and Iron metal 

Ans. Aluminium metal is more reactive than Iron metal, so displacement reaction will occur between FeSO4 and aluminium metal.

7. Why does zinc react with sulphuric acid to give hydrogen gas but copper does not?

a. Zinc is more reactive

b. Copper is more reactive

c. The statement is incorrect

d. None of the above

Ans. Zinc is more reactive than hydrogen. Hence, it can react with sulphuric acid to give hydrogen gas.

8. What would you observe when you put some aluminium pieces in copper sulphate solution?

a. Solution will become green

b. Solution will become colourless

c. Solution will become grey

d. Solution will become black

Ans. Copper sulphate solution is blue. When we put some aluminium pieces in copper sulphate solution, the blue colour disappears and the solution becomes colourless.

9. Food cans are coated with tin and not with zinc because:

a. Zinc is costly

b. Zinc has higher melting point

c. Zinc is less reactive than tin

d. Zinc is more reactive than tin

Ans. Food cans are coated with tin and not with zinc because Zinc is more reactive than tin.

10. Metal "P" is able to remove Metal "Q" from its salt solution, whereas Metal "R" cannot be removed from its salt solution. Choose the metal that is least reactive.

a. P

b. Q

c. R

d. Cannot be determined

Ans. Q is the least reactive metal.

Conclusion

From the metal reactivity series experiment, we can conclude that the most reactive metals are ranked at the top of the reactivity series, and the least reactive metals are ranked at the bottom. A collection of metals arranged in decreasing order of reactivity is called a metal reactivity series. It is occasionally referred to as an activity series. Either the electrical make-up of metals or the half filled outer orbitals are responsible for their reactivity. Positively charged ions result when metals lose electrons. Higher atomic number metals are more reactive as a result of the electrons' distance from the positively charged nucleus. From this, it can be concluded that aluminium is the most reactive and copper is the least reactive among the given four metals (Fe, Zn, Cu, and Al). Thus, the decreasing order of reactivity of metals is

Al > Zn > Fe > Cu