Class 10th Science Lab Manual CBSE Solution
Lab Experiment 3Viva Questions- What is the basic principle involved in this experiment?
- Why is there is a difference in reactivity of different metals?
- Which reaction is used to determine the relative reactivities of metals? Define the type…
- Name the most reactive the least reactive metal.
- Which is more reactive Zinc or copper? How do you know that?
- What does the reactivity series of metals indicate? And why it is needed.…
- What will happen when an iron nail is dipped in a copper sulphate solution?…
- Why are gold and silver used for ornaments?
- Can we store ZnSO4 solution in Al vessel?
- Describe the colors of the following solutions: (i) Copper Sulphate (ii) Ferrous Sulphate…
- Describe the colors of the following metals: (i) Zinc (Zn) (ii) Iron (Fe) (iii) Copper…
- Arrange the following metals in decreasing order of reactivity. Zn, Cu, Fe, Al…
- What materials will you use for comparing the reactivities of Aluminium and Iron? Give a…
- What is a salt? Give names of salts that you use in day-to-day life.…
- Why is salt used in determining the reactivities of metals?
- What will happen if a less reactive metal reatcs with a salt of higher reactive metal?…
- Why do we need to clean the metals with sandpaper prior to the experiment?…
- Complete the following reactions- i. Cu + Al2(SO4)3 ⇒ ii. Cu + CuSO4 ⇒ iii. Zn + FeSO4⇒…
- Can Copper displace hydrogen from acids water?
- Complete the reaction give reason: Zn + H2O →
- What is the basic principle involved in this experiment?
- Why is there is a difference in reactivity of different metals?
- Which reaction is used to determine the relative reactivities of metals? Define the type…
- Name the most reactive the least reactive metal.
- Which is more reactive Zinc or copper? How do you know that?
- What does the reactivity series of metals indicate? And why it is needed.…
- What will happen when an iron nail is dipped in a copper sulphate solution?…
- Why are gold and silver used for ornaments?
- Can we store ZnSO4 solution in Al vessel?
- Describe the colors of the following solutions: (i) Copper Sulphate (ii) Ferrous Sulphate…
- Describe the colors of the following metals: (i) Zinc (Zn) (ii) Iron (Fe) (iii) Copper…
- Arrange the following metals in decreasing order of reactivity. Zn, Cu, Fe, Al…
- What materials will you use for comparing the reactivities of Aluminium and Iron? Give a…
- What is a salt? Give names of salts that you use in day-to-day life.…
- Why is salt used in determining the reactivities of metals?
- What will happen if a less reactive metal reatcs with a salt of higher reactive metal?…
- Why do we need to clean the metals with sandpaper prior to the experiment?…
- Complete the following reactions- i. Cu + Al2(SO4)3 ⇒ ii. Cu + CuSO4 ⇒ iii. Zn + FeSO4⇒…
- Can Copper displace hydrogen from acids water?
- Complete the reaction give reason: Zn + H2O →
Lab Experiment 3
Question 1.AIM
(i) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions :
(a) ZnSO4(aq.)
(b) FeSO4(aq.)
(c) CuSO4(aq.)
(d) Al2(SO4)3(aq.)
(ii) To arrange Zn, Fe, Cu and Al (metals) in the decreasing order of reactivity based on the above result.
Answer:MATERIALS REQUIRED
Apparatus: Test tubes, test stand,
Chemical Compounds: Metals-Zn granules, Fe filings, Cu turnings, Al foil and aqueous solutions of zinc sulphate, ferrous sulphate, copper sulphate, and aluminium sulphate.
THEORY
Metals are elements which are good conductors of heat and electricity. Most metals lose electrons in chemical reactions to become electropositive. The alkali metal comprises group 1 of the periodic table.
1. The metals have been arranged in the decreasing order of reactivity in a series. This series is known as the reactivity or activity series.
2. The reactivity series of metals is used for predicting the products of displacement reactions and the reactivity of metals in other reactions. Potassium is the most reactive metal, while platinum is the least reactive.
3. A more reactive metal can displace less reactive metals from its salt solution or compounds If metal C displaces metal B from its salt solution, but metal A displaces metal C from its salt solution it follows that the increasing order of reactivity is :
B < C < A.
4. Displacement reactions are prevalent in metals due to the relative strength of metal to displace other metals from their salt solution. In a displacement reaction, a more reactive metal can displace a less reactive metal from its salt solution. The reaction is often known as metal displacement reaction.
When zinc granules are immersed in the copper sulphate solution, the initial colour of copper sulphate from blue starts get changed to colourless with reddish brown particles of pure copper settle at the bottom of the test tube. This chemical change for the following reaction :
Some other displacement reactions using zinc and iron are as follows :
Colour of solutions and metals
PROCEDURE
1. Take four clean, dry test tubes and label them as 'A', 'B', 'C' and 'D'.
2. Pour 10 ml of the given aqueous solution into their respective test tubes.
3. Add a small piece of Aluminum foil to each of these test tubes.
4. Observe the changes and record your observations.
5. Repeat the above steps using :
(a) Copper turnings with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
(b) Iron filings with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
(c) Zinc granules with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
6. Record your observations in the following table :
OBSERVATIONS :
1. When aluminium foil (Al) is added to all the 4 test tubes:
2. When copper turnings (Cu) are added to all the 4 test tubes:
3. When iron fillings are added in all the 4 test tubes:
4. When Zinc granules are added in all the 4 test tubes:
RESULT
1. Aluminium can displace Fe, Cu, and Zn from their salt solutions. Therefore Aluminum is most reactive among them.
2. Copper is unable to displace any metal among Al, Fe, and Zn from their salt solutions. Therefore Cu is the least reactive element among them.
3. Iron being less reactive than zinc is unable to displace Zn from its salt solution, whereas Zn can displace Fe from its salt solution. Therefore Zn is more reactive than Fe.
4. The decreasing order of reactivity for metals are as follows :
Al > Zn > Fe > Cu.
PRECAUTIONS
1. Handle the chemicals with care.
2. Clean each metal using sandpaper to remove the oxide layer.
3. Observe the changes patiently as few reactions may occur slowly.
4. Never taste the chemicals.
5. Rinse the test tube properly with water before use.
AIM
(i) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions :
(a) ZnSO4(aq.)
(b) FeSO4(aq.)
(c) CuSO4(aq.)
(d) Al2(SO4)3(aq.)
(ii) To arrange Zn, Fe, Cu and Al (metals) in the decreasing order of reactivity based on the above result.
Answer:
MATERIALS REQUIRED
Apparatus: Test tubes, test stand,
Chemical Compounds: Metals-Zn granules, Fe filings, Cu turnings, Al foil and aqueous solutions of zinc sulphate, ferrous sulphate, copper sulphate, and aluminium sulphate.
THEORY
Metals are elements which are good conductors of heat and electricity. Most metals lose electrons in chemical reactions to become electropositive. The alkali metal comprises group 1 of the periodic table.
1. The metals have been arranged in the decreasing order of reactivity in a series. This series is known as the reactivity or activity series.
2. The reactivity series of metals is used for predicting the products of displacement reactions and the reactivity of metals in other reactions. Potassium is the most reactive metal, while platinum is the least reactive.
3. A more reactive metal can displace less reactive metals from its salt solution or compounds If metal C displaces metal B from its salt solution, but metal A displaces metal C from its salt solution it follows that the increasing order of reactivity is :
B < C < A.
4. Displacement reactions are prevalent in metals due to the relative strength of metal to displace other metals from their salt solution. In a displacement reaction, a more reactive metal can displace a less reactive metal from its salt solution. The reaction is often known as metal displacement reaction.
When zinc granules are immersed in the copper sulphate solution, the initial colour of copper sulphate from blue starts get changed to colourless with reddish brown particles of pure copper settle at the bottom of the test tube. This chemical change for the following reaction :
Some other displacement reactions using zinc and iron are as follows :
Colour of solutions and metals
PROCEDURE
1. Take four clean, dry test tubes and label them as 'A', 'B', 'C' and 'D'.
2. Pour 10 ml of the given aqueous solution into their respective test tubes.
3. Add a small piece of Aluminum foil to each of these test tubes.
4. Observe the changes and record your observations.
5. Repeat the above steps using :
(a) Copper turnings with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
(b) Iron filings with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
(c) Zinc granules with ZnSO4, FeSO4, CuSO4, and Al2(SO4)3 solutions.
6. Record your observations in the following table :
OBSERVATIONS :
1. When aluminium foil (Al) is added to all the 4 test tubes:
2. When copper turnings (Cu) are added to all the 4 test tubes:
3. When iron fillings are added in all the 4 test tubes:
4. When Zinc granules are added in all the 4 test tubes:
RESULT
1. Aluminium can displace Fe, Cu, and Zn from their salt solutions. Therefore Aluminum is most reactive among them.
2. Copper is unable to displace any metal among Al, Fe, and Zn from their salt solutions. Therefore Cu is the least reactive element among them.
3. Iron being less reactive than zinc is unable to displace Zn from its salt solution, whereas Zn can displace Fe from its salt solution. Therefore Zn is more reactive than Fe.
4. The decreasing order of reactivity for metals are as follows :
Al > Zn > Fe > Cu.
PRECAUTIONS
1. Handle the chemicals with care.
2. Clean each metal using sandpaper to remove the oxide layer.
3. Observe the changes patiently as few reactions may occur slowly.
4. Never taste the chemicals.
5. Rinse the test tube properly with water before use.
Viva Questions
Question 1.What is the basic principle involved in this experiment?
Answer:The basic principle involved in this experiment is that displacement reaction taking place due to the reactivity series of metals.
Question 2.Why is there is a difference in reactivity of different metals?
Answer:All metals differ in the number of valence electrons and number of valence shell. Due to this, they have different tendency to lose electrons and thus have a difference in reactivities.
Question 3.Which reaction is used to determine the relative reactivities of metals? Define the type of reaction.
Answer:Displacement reaction is used to determine relative reactivities of metals.
Displacement Reaction: A single displacement reaction is also called a substitution reaction. In these reactions, a free element displaces another element from its compound, producing a new compound. The basic format of the reaction can be written as:
A + BX → AX + B
Question 4.Name the most reactive & the least reactive metal.
Answer:Potassium (K) is the most reactive metal, and gold (Au) is the least reactive metal.
Question 5.Which is more reactive Zinc or copper? How do you know that?
Answer:Zinc is more reactive than copper. During the reaction of Zinc with Copper sulphate solution, zinc displaces copper from the solution making a blue solution of copper sulphate colorless.
The reaction is below:
Question 6.What does the reactivity series of metals indicate? And why it is needed.
Answer:Reactivity series of metals indicate that the metals that are high in reactivity series displace metals that are low in reactivity series. This series helps us to know which metal displaces which metal and helps in electrolysis and many more reactions to get the final product.
Question 7.What will happen when an iron nail is dipped in a copper sulphate solution?
Answer:When an iron nail is dipped in copper sulphate solution, as iron is higher in reactivity series it will displace copper from its salt. This will make the change in color of copper sulphate from blue to pale green. The reaction looks like:
Fe2+(s) + Cu2+(aq) → Fe2+(aq) + Cu2+(s)
Question 8.Why are gold and silver used for ornaments?
Answer:Gold and silver are very less reactive. Due to which they can last longer without being affected by air and moisture and thus retains their luster.
Question 9.Can we store ZnSO4 solution in Al vessel?
Answer:No, we can not store ZnSO4 solution in Al vessel.
Reason: Al being more reactive than zinc will displace zinc from the solution and the vessel will be distorted.
Reaction Involved:
Al3+(s) + Zn2+(aq) → Al3+(aq) + Zn2+(s)
Question 10.Describe the colors of the following solutions:
(i) Copper Sulphate
(ii) Ferrous Sulphate
(iii) Zinc Sulphate
(iv) Aluminum Sulphate
Answer:(i) Copper Sulphate - Blue
(ii) Ferrous Sulphate – Pale Green
(iii) Zinc Sulphate – Colourless
(iv) Aluminum Sulphate – Colourless
Question 11.Describe the colors of the following metals:
(i) Zinc (Zn)
(ii) Iron (Fe)
(iii) Copper (Cu)
(iv) Aluminum (Al)
Answer:(i) Zinc – Silvery White (Greyish)
(ii) Iron – Blackish Grey
(iii) Copper – Reddish Brown
(iv) Aluminum – White
Question 12.Arrange the following metals in decreasing order of reactivity.
Zn, Cu, Fe, Al
Answer:The reactivities of metals are:
Hence,
Al > Zn > Fe > Cu
Question 13.What materials will you use for comparing the reactivities of Aluminium and Iron? Give a reaction.
Answer:We will use Ferrous Sulphate solution (FeSO4) and Aluminium foil for comparing the reactivities of zinc and iron.
Reaction:
Question 14.What is a salt? Give names of salts that you use in day-to-day life.
Answer:An ionic compound which contains a cation(+ve) and anion(-ve) other than (H+) and (OH-1) is called a salt. The commonly used salts are:
i. Common Salt - NaCl
ii. Baking Soda – NaHCO3
Question 15.Why is salt used in determining the reactivities of metals?
Answer:Salts are ionic compounds and thus follow single displacement reaction with metals. Due to which a metal can displace other metals from its salt.
Reaction:
A + BX → AX + B
Where A is metal and BX is a salt of B(metal). After the reaction, A displaces B from its salt and AX is formed leaving behind B.
Question 16.What will happen if a less reactive metal reatcs with a salt of higher reactive metal?
Answer:No solution will take place.
Reason: As the less reactive metal could not displace the high reactive metal, no reaction will take place.
Question 17.Why do we need to clean the metals with sandpaper prior to the experiment?
Answer:Metals may contain some impurities prior to experiment. These impurities can cause hindrance during reaction so to get proper observation metals are cleaned with sandpaper.
Question 18.Complete the following reactions-
i. Cu + Al2(SO4)3 ⇒
ii. Cu + CuSO4 ⇒
iii. Zn + FeSO4⇒
Answer:i. Cu + Al2(SO4)3 ⇒ No change observed
Explanation: Because copper (Cu) is less reactive than aluminium (Al), it cannot displace Al from its salt solution. Hence, no change observed.
ii. Cu + CuSO4 ⇒ No change observed
Explanation: A metal cannot displace itself from its salt solution. Hence, no change is observed.
iii. Zn + FeSO4⇒ Because Zn is more reactive than Iron (Fe), hence Zn displaces Fe from its salt solution. The original pale green solution FeSO4 becomes colourless.
Question 19.Can Copper displace hydrogen from acids & water?
Answer:No, copper cannot displace hydrogen from acids and water. This is because, all the metal which lie below the position of “hydrogen” in the reactivity series, are less reactive than hydrogen, hence, these metals cannot displace hydrogen from acids & water.
Question 20.Complete the reaction & give reason:
Zn + H2O →
Answer:The complete reaction is Zn + H2O → Zn(OH)2 + H2
Zn is more reactive than hydrogen, as it lies above hydrogen in the reactivity series. Hence, Zn displaces H from water and forms zinc hydroxide i.e. Zn(OH)2
What is the basic principle involved in this experiment?
Answer:
The basic principle involved in this experiment is that displacement reaction taking place due to the reactivity series of metals.
Question 2.
Why is there is a difference in reactivity of different metals?
Answer:
All metals differ in the number of valence electrons and number of valence shell. Due to this, they have different tendency to lose electrons and thus have a difference in reactivities.
Question 3.
Which reaction is used to determine the relative reactivities of metals? Define the type of reaction.
Answer:
Displacement reaction is used to determine relative reactivities of metals.
Displacement Reaction: A single displacement reaction is also called a substitution reaction. In these reactions, a free element displaces another element from its compound, producing a new compound. The basic format of the reaction can be written as:
A + BX → AX + B
Question 4.
Name the most reactive & the least reactive metal.
Answer:
Potassium (K) is the most reactive metal, and gold (Au) is the least reactive metal.
Question 5.
Which is more reactive Zinc or copper? How do you know that?
Answer:
Zinc is more reactive than copper. During the reaction of Zinc with Copper sulphate solution, zinc displaces copper from the solution making a blue solution of copper sulphate colorless.
The reaction is below:
Question 6.
What does the reactivity series of metals indicate? And why it is needed.
Answer:
Reactivity series of metals indicate that the metals that are high in reactivity series displace metals that are low in reactivity series. This series helps us to know which metal displaces which metal and helps in electrolysis and many more reactions to get the final product.
Question 7.
What will happen when an iron nail is dipped in a copper sulphate solution?
Answer:
When an iron nail is dipped in copper sulphate solution, as iron is higher in reactivity series it will displace copper from its salt. This will make the change in color of copper sulphate from blue to pale green. The reaction looks like:
Fe2+(s) + Cu2+(aq) → Fe2+(aq) + Cu2+(s)
Question 8.
Why are gold and silver used for ornaments?
Answer:
Gold and silver are very less reactive. Due to which they can last longer without being affected by air and moisture and thus retains their luster.
Question 9.
Can we store ZnSO4 solution in Al vessel?
Answer:
No, we can not store ZnSO4 solution in Al vessel.
Reason: Al being more reactive than zinc will displace zinc from the solution and the vessel will be distorted.
Reaction Involved:
Al3+(s) + Zn2+(aq) → Al3+(aq) + Zn2+(s)
Question 10.
Describe the colors of the following solutions:
(i) Copper Sulphate
(ii) Ferrous Sulphate
(iii) Zinc Sulphate
(iv) Aluminum Sulphate
Answer:
(i) Copper Sulphate - Blue
(ii) Ferrous Sulphate – Pale Green
(iii) Zinc Sulphate – Colourless
(iv) Aluminum Sulphate – Colourless
Question 11.
Describe the colors of the following metals:
(i) Zinc (Zn)
(ii) Iron (Fe)
(iii) Copper (Cu)
(iv) Aluminum (Al)
Answer:
(i) Zinc – Silvery White (Greyish)
(ii) Iron – Blackish Grey
(iii) Copper – Reddish Brown
(iv) Aluminum – White
Question 12.
Arrange the following metals in decreasing order of reactivity.
Zn, Cu, Fe, Al
Answer:
The reactivities of metals are:
Hence,
Al > Zn > Fe > Cu
Question 13.
What materials will you use for comparing the reactivities of Aluminium and Iron? Give a reaction.
Answer:
We will use Ferrous Sulphate solution (FeSO4) and Aluminium foil for comparing the reactivities of zinc and iron.
Reaction:
Question 14.
What is a salt? Give names of salts that you use in day-to-day life.
Answer:
An ionic compound which contains a cation(+ve) and anion(-ve) other than (H+) and (OH-1) is called a salt. The commonly used salts are:
i. Common Salt - NaCl
ii. Baking Soda – NaHCO3
Question 15.
Why is salt used in determining the reactivities of metals?
Answer:
Salts are ionic compounds and thus follow single displacement reaction with metals. Due to which a metal can displace other metals from its salt.
Reaction:
A + BX → AX + B
Where A is metal and BX is a salt of B(metal). After the reaction, A displaces B from its salt and AX is formed leaving behind B.
Question 16.
What will happen if a less reactive metal reatcs with a salt of higher reactive metal?
Answer:
No solution will take place.
Reason: As the less reactive metal could not displace the high reactive metal, no reaction will take place.
Question 17.
Why do we need to clean the metals with sandpaper prior to the experiment?
Answer:
Metals may contain some impurities prior to experiment. These impurities can cause hindrance during reaction so to get proper observation metals are cleaned with sandpaper.
Question 18.
Complete the following reactions-
i. Cu + Al2(SO4)3 ⇒
ii. Cu + CuSO4 ⇒
iii. Zn + FeSO4⇒
Answer:
i. Cu + Al2(SO4)3 ⇒ No change observed
Explanation: Because copper (Cu) is less reactive than aluminium (Al), it cannot displace Al from its salt solution. Hence, no change observed.
ii. Cu + CuSO4 ⇒ No change observed
Explanation: A metal cannot displace itself from its salt solution. Hence, no change is observed.
iii. Zn + FeSO4⇒ Because Zn is more reactive than Iron (Fe), hence Zn displaces Fe from its salt solution. The original pale green solution FeSO4 becomes colourless.
Question 19.
Can Copper displace hydrogen from acids & water?
Answer:
No, copper cannot displace hydrogen from acids and water. This is because, all the metal which lie below the position of “hydrogen” in the reactivity series, are less reactive than hydrogen, hence, these metals cannot displace hydrogen from acids & water.
Question 20.
Complete the reaction & give reason:
Zn + H2O →
Answer:
The complete reaction is Zn + H2O → Zn(OH)2 + H2
Zn is more reactive than hydrogen, as it lies above hydrogen in the reactivity series. Hence, Zn displaces H from water and forms zinc hydroxide i.e. Zn(OH)2
