RBSE Class 10 Science Chapter 1 Activity 1.6 Solution- Chemical Reactions and Equations

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Activity   1.6 of chapter Chemical Reactions and Equations helps students understand the effect of heat and lead nitrate. This activity demonstrates the concept of thermal decomposition which is an important topic in Class 10 Science.

RBSE Class 10 Science Chapter 1 Activity 1.6 Solution- Chemical Reactions and Equations

 

Activity 1.6 Class 10 Science

 

Objective

To observe the effect of heat on lead nitrate powder and identify the changes due to its thermal decomposition

Material Required

  1. Boiling tube
  2. Lead nitrate powder
  3. Tongues
  4. Spirit lamp or burner

Procedure

RBSE Class 10 Science Chapter 1 Activity 1.6 Solution

  • Take about 2 g of lead nitrate powder in a dry boiling tube.
  • Hold the boiling tube with the help of tongs.
  • Heat the boiling tube over the flame of a spirit lamp or burner.
  • Observe the colour change of the solid and the gases evolved during heating.

Observation

  • Lead nitrate is initially a white powder.
  • On heating the white powder turns yellow.
  • Reddish brown fumes are evolved during the reaction.
  • A pungent smell is noticed due to the gases released.
  • A yellow residue of lead oxide remains in the boiling tube after heating.

 Chemical Reaction

 2Pb(NO3)2 (s)      →   2PbO(s) +4NO2(g)+O2(g)

Explanation

Lead nitrate is a white crystalline that undergoes thermal decomposition when heated. During heating, lead nitrate breakes down into lead oxide, nitrogen dioxide and oxygen.

 Lead oxide is yellow in colour and remains as a solid residue in the boiling tube.

Nitrogen dioxide is a reddish-brown gas with a pungent smell, while oxygen gas is also released during the reaction.

Since the compound decomposes into simpler substances on heating, the reaction is known as a thermal decomposition reaction.

 Type of Chemical Reaction

 Thermal decomposition reaction

A reaction in which a compound breaks down into two or more simpler substances by the action of heat is called a thermal decomposition reaction.

 

Conclusion

This activity shows the thermal decomposition of lead nitrate that produces lead oxide, nitrogen dioxide and oxygen.

Precaution: Do not point the mouth of boiling tube at neighbours or yourself.

Precautions  

  • Do not point the mouth of the boiling tube towards yourself or others.
  • Use tongs while heating the boiling tube.
  • Perform the activity under the supervision of a teacher.
  • Avoid inhaling the reddish-brown nitrogen dioxide gas.
  • Handle hot apparatus carefully.

 

Viva Questions and Answers

Q1. What is the colour of lead nitrate before heating?

Answer – White

Q2. What is the colour of lead oxide formed after heating?

Answer – Yellow

Q3. Which reddish brown gas is evolved during the reaction?

Answer – Nitrogen dioxide

Q4. Which other gas is produced during the reaction in this activity?

Answer – Oxygen

Q5. What type of reaction is demonstrated in this activity?

Answer – Thermal decomposition reaction

Q6. Why is the reaction called thermal decomposition?

Answer – Because lead nitrate breaks down into simpler substances when heated.

Q7. Which solid substance remains in the boiling tube after heating?

Answer -Lead oxide

 Key Learning Points

  • Lead nitrate is a white crystalline compound.
  • On heating , it decomposes into lead oxide, nitrogen dioxide and oxygen.
  • Lead oxide is yellow in colour.
  • Nitrogen dioxide is a reddish-brown gas with a pungent smell.
  • The reaction is a thermal decomposition reaction.
  • Heat causes a single compound to break down into simpler substances.

 

Multiple Choice Questions

 

1.Write the chemical formula of lead nitrate.

  1. Pb(NO3)2
  2. PbNO2
  3. Pb(NO)2
  4. d.none of the above

correct answer – (a) Pb(NO3)2

2.Of which colour fumes evolve when lead nitrate is heated in the boiling tube?

  1. Reddish brown fumes
  2. Yellow
  3. Red
  4. Brown

Correct answer – (a) Reddish brown fumes

3.What is the colour of residue remains in the boiling tube in the given activity?

  1. Red
  2. b.Yellow
  3. c.Reddish brown
  4. d.white

 

correct answer – (b) Yellow

4.Name the reaction takes place in this activity 1.6.

  1. Displacement reaction
  2. Combination reaction
  3. Double displacement reaction
  4. Decomposition reaction

Correct answer – (d) Decomposition reaction

5.Name the substance left as residue in the boiling tube.

  1. lead oxide
  2. lead dioxide
  3. lead nitrate
  4. None of the above

correct answer – (a) Lead oxide

6.What is the colour of lead nitrate?

  1. yellow
  2. Brwon
  3. White
  4. Green

Correct answer – (c) White

7.Which gas is also produced during the decomposition of lead nitrate?

  1. Oxygen
  2. Hydrogen
  3. Nitrogen dioxide
  4. Carbon di oxide

correct answer – ( c) Nitrogen dioxide

8.What causes the pungent smell during the reaction?

  1. Oxygen
  2. Nitrogen dioxide gas
  3. Water vapour
  4. Lead oxide

Correct answer – ( b) Nitrogen dioxide

Related Topics 

RBSE Class 10 Science Activities Solutions