NCERT Solutions Science Class 10 Chapter 1 Chemical Reactions and Equations

Chemical Reactions and Equations is the first chapter of Class 10 Science. This chapter covers the basics of chemical equations, various types of chemical reactions, and the concepts of corrosion and rancidity. It helps students in grasping how substances interact and change during chemical reactions, a fundamental concept that forms the backbone of chemistry in higher classes. By learning to balance chemical equations, students develop an understanding of the conservation of mass and how to represent chemical changes symbolically. Exploring different types of reactions—such as combination, decomposition, displacement, and redox reactions—enables students to classify and predict the outcomes of chemical processes. The chapter also discusses corrosion and rancidity, helping students relate these scientific principles to everyday phenomena, making their learning more relevant and practical.

1.0Download NCERT Solutions for Class 10 Science Chapter 1 PDF

This article offers chemical reactions and equations class 10 solutions as per NCERT. Practicing these solutions will help students develop a strong foundation in chemistry and gain clarity on how to approach related problems effectively, ultimately aiding in securing good scores in board exams. For a detailed understanding, students can download the NCERT Solutions for class 10 science chapter 1 chemical reactions and equation exercise solution below, curated by ALLEN’s experts.

2.0Class 10 Science Chapter 1 Chemical Reactions and Equations Overview

Before getting into the details of class 10 chemical reactions and equation ncert solutions, let's take a brief look at the topics and subtopics covered in this chapter of the NCERT Class 10 Science book.

Topics covered in this chapter:

• Introduction
• Chemical Equations
• Types of Chemical Reactions
• Corrosion
• Rancidity

3.0Summary of Chemical Reactions and Equations Class 10 Science Chapter 1

A chemical reaction is a process in which substances (reactants) are transformed into new substances (products) by breaking and forming chemical bonds. This transformation can be observed through changes like colour shifts, gas formation, precipitation, or temperature changes. For example, the rusting of iron is represented by the equation: 4Fe + 3O₂ → 2Fe₂O₃.

Chemical equations symbolize reactions, with reactants on the left and products on the right, separated by an arrow (→). For example, the reaction of hydrogen and oxygen to form water is: 2H₂ + O₂ → 2H₂O. Balancing equations ensures the conservation of mass, meaning the number of atoms of each element must be the same on both sides. To balance, adjust the coefficients before the formulas, ensuring they are in the simplest whole-number ratio.

Chemical reactions are classified into several types:

1. Combination Reactions: Two or more reactants form a single product (e.g., 2H₂ + O₂ → 2H₂O).
2. Decomposition Reactions: A compound breaks down into simpler substances (e.g., 2H₂O₂ → 2H₂O + O₂).
3. Displacement Reactions: One element replaces another (e.g., Zn + CuSO₄ → ZnSO₄ + Cu).
4. Double Displacement Reactions: Two compounds exchange ions (e.g., Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl).
5. Redox Reactions: One substance is oxidized (loses electrons), and another is reduced (gains electrons) (e.g., ZnO + C → Zn + CO).

Observations indicating a chemical reaction include color change, gas evolution, precipitate formation, and temperature change. Corrosion (e.g., rusting) and rancidity (e.g., oxidation of fats) are common real-life examples of chemical changes. To prevent rancidity, antioxidants are used, and foods are stored in airtight conditions.

4.0Class 10 Science Chapter 1 Chemical Reactions and Equations NCERT : Detailed Solutions

1. Why should a magnesium ribbon be cleaned before it is burnt in air?

Answer: Magnesium is an extremely reactive metal. When stored, it reacts with oxygen to form a layer of magnesium oxide on its surface. This layer of magnesium oxide is quite stable and prevents further reaction of magnesium with oxygen. The magnesium ribbon is cleaned by sand paper for removing this layer so that the underlying metal can be exposed to air.

2. Write the balanced equation for the following chemical reactions.

(i) Hydrogen + Chlorine → Hydrogen chloride

(ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride

(iii) Sodium + Water → Sodium hydroxide + Hydrogen

Answer: (i) H₂(g) + Cl₂(g) → 2HCl(g)

(ii) 3BaCl₂(aq) + Al₂(SO₄)₃(aq) → 3BaSO₄(s) + 2AlCl₃(aq)

(iii) 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

3. Write a balanced chemical equation with state symbols for the following reactions.

(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.

(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.

Answer:(i) BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)

(ii) NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

4. A solution of a substance 'X' is used for white washing.

(i) Name the substance 'X' and write its formula.

(ii) Write the reaction of the substance 'X' with water.

Answer: (i) The substance 'X' is calcium oxide. Its chemical formula is CaO (Also known as quick lime).

(ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime).

$\text{CaO}(s)+{\text{H}}_2\text{O}(\ell )\to {\text{Ca(OH)}}_2(aq)$

5. Why is the amount of gas collected in one of the test tubes in Active Chemistry 7 double the amount collected in the other? Name this gas.

Answer: Water (H₂O) contains two parts of hydrogen and one part of oxygen. Therefore, the amount of hydrogen and oxygen produced during the electrolysis of water is in a ratio of 2:1. During electrolysis, since hydrogen goes to one test tube and oxygen goes to another, the amount of gas collected in one of the test tubes is double the amount collected in the other.

The reaction is: 2H₂O(l) → 2H₂(g) + O₂(g)

The amount of hydrogen gas (H₂) collected would be double that of oxygen gas (O₂).

6. Why does the color of copper sulfate solution change when an iron nail is dipped in it?

Answer: When an iron nail is placed in a copper sulfate solution, iron displaces copper from the copper sulfate solution, forming iron sulfate, which is green in color.

The reaction is: Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

Therefore, the blue color of the copper sulfate solution fades, and a green color appears.

7. Give an example of a double displacement reaction other than the one given in Active Chemistry 11.

Answer: Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride.

The reaction is: Na₂CO₃(aq) + CaCl₂(aq) → CaCO₃(s) + 2NaCl(aq)

In this reaction, sodium carbonate and calcium chloride exchange their ions mutually to form two new compounds. Hence, it is a double displacement reaction.

8. Identify the substances that are oxidized and the substances that are reduced in the following reactions:

(i) 4Na(s) + O₂(g) → 2Na₂O(s)

(ii) CuO(s) + H₂(g) → Cu(s) + H₂O(l)

Answer:

(i) Sodium (Na) is oxidized as it gains oxygen, and oxygen (O₂) is reduced.

(ii) Copper oxide (CuO) is reduced to copper (Cu), while hydrogen (H₂) is oxidized to water (H₂O).

9. Which of the statements about the reaction below are incorrect?

2PbO(s) + C(s) → 2Pb(s) + CO₂(g)

(1) Lead is getting reduced.

(2) Carbon dioxide is getting oxidized.

(3) Carbon is getting oxidized.

(4) Lead oxide is getting reduced.

(a) (1) and (2)

(b) (1) and (3)

(c) (1), (2), and (3)

(d) All of these

Answer: (a) (1) and (2)

Carbon is getting oxidized into CO₂, while PbO is getting reduced into Pb.

10. Fe₂O₃ + 2Al → Al₂O₃ + 2Fe

The above reaction is an example of a:

(a) combination reaction.

(b) double displacement reaction.

(c) decomposition reaction.

(d) displacement reaction.

Answer: (d) The given reaction is an example of a displacement reaction.

11. What happens when dilute hydrochloric acid is added to iron filings? Tick the correct answer.

(a) Hydrogen gas and iron chloride are produced.

(b) Chlorine gas and iron hydroxide are produced.

(c) No reaction takes place.

(d) Iron salt and water are produced.

Answer: (a) Hydrogen gas and iron chloride are produced. The reaction is: Fe(s) + 2HCl(aq) → FeCl₂(aq) + H₂↑

12. What is a balanced chemical equation? Why should chemical equations be balanced?

Answer: A reaction which has an equal number of atoms of each element on both sides of the chemical equation is called a balanced chemical equation.

The law of conservation of mass states that mass can neither be created nor destroyed. Hence, in a chemical reaction, the total mass of reactants should be equal to the total mass of the products. It means that the total number of atoms of each element should be equal on both sides of a chemical equation. Hence, it is for this reason that chemical equations should be balanced.

13. Translate the following statements into chemical equations and then balance them.

(a) Hydrogen gas combines with nitrogen to form ammonia.

(b) Hydrogen sulfide gas burns in air to give water and sulfur dioxide.

(c) Barium chloride reacts with aluminum sulfate to give aluminum chloride and a precipitate of barium sulfate.

(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Answer:

(a) 3H₂(g) + N₂(g) → 2NH₃(g)

(b) 2H₂S(g) + 3O₂(g) → 2H₂O(l) + 2SO₂(g)

(c) 3BaCl₂(aq) + Al₂(SO₄)₃(aq) → 2AlCl₃(aq) + 3BaSO₄(s)

(d) 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g)

14. Balance the following chemical equations.

(a) HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + H₂O

(b) NaOH + H₂SO₄ → Na₂SO₄ + H₂O

(c) NaCl + AgNO₃ → AgCl + NaNO₃

(d) BaCl₂ + H₂SO₄ → BaSO₄ + HCl

Answer:

(a) 2HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + 2H₂O

(b) 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

(c) NaCl + AgNO₃ → AgCl + NaNO₃

(d) BaCl₂ + H₂SO₄ → BaSO₄ + 2HCl

15. Write the balanced chemical equations for the following reactions.

(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water

(b) Zinc + Silver nitrate → Zinc nitrate + Silver

(c) Aluminum + Copper chloride → Aluminum chloride + Copper

(d) Barium chloride + Potassium sulfate → Barium sulfate + Potassium chloride

Answer:

(a) Ca(OH)₂ + CO₂ → CaCO₃ + H₂O

(b) Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag

(c) 2Al + 3CuCl₂ → 2AlCl₃ + 3Cu

(d) BaCl₂ + K₂SO₄ → BaSO₄ + 2KCl

16. Write the balanced chemical equation for the following and identify the type of reaction in each case.

(a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)

(b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)

(c) Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)

(d) Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq) + Hydrogen(g)

Answer:

(a) 2KBr(aq) + BaI₂(aq) → 2KI(aq) + BaBr₂(s); Double displacement reaction

(b) ZnCO₃(s) → ZnO(s) + CO₂(g); Decomposition reaction

(c) H₂(g) + Cl₂(g) → 2HCl(g); Combination reaction

(d) Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g); Displacement reaction

17. What does one mean by exothermic and endothermic reactions? Give examples.

Answer:

Chemical reactions that release energy in the form of heat are called exothermic reactions.

Example: Na(s) + ½Cl₂(s) → NaCl(s) + 411 kJ of energy

Reactions that absorb energy or require energy in order to proceed are called endothermic reactions.

Example: 6CO₂(g) + 6H₂O(l) → (Sunlight) C₆H₁₂O₆(aq) + 6O₂(g)

18. Why is respiration considered an exothermic reaction? Explain.

Answer: Energy is released during respiration, a process where glucose combines with oxygen in cells to produce carbon dioxide, water, and energy.

The reaction is: C₆H₁₂O₆(aq) + 6O₂(g) → 6CO₂(g) + 6H₂O(l) + Energy

19. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Answer: Decomposition reactions break down a compound into simpler substances using energy, while combination reactions combine substances to form a new compound, releasing energy.

Decomposition: AB + Energy → A + B (e.g., 2H₂O(l) → 2H₂(g) + O₂(g))

Combination: A + B → AB + Energy (e.g., 2H₂(g) + O₂(g) → 2H₂O(l))

20. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light, or electricity.

Answer:

(a) Thermal decomposition: 2FeSO₄(s) → Fe₂O₃(s) + SO₂(g) + SO₃(g)

(b) Decomposition by light: 2AgCl(s) → 2Ag(s) + Cl₂(g)

(c) Decomposition by electricity: 2Al₂O₃(aq) → 4Al(s) + 3O₂(g)

21. What is the difference between displacement and double displacement reactions? Write equations for these reactions.

Answer: Displacement: A + BX → AX + B (e.g., CuSO₄(aq) + Zn(s) → ZnSO₄(aq) + Cu(s))

Double displacement: AB + CD → AD + CB (e.g., Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s) + 2NaCl(aq))

22. In the refining of silver, the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.

Answer: 2AgNO₃(aq) + Cu(s) → Cu(NO₃)₂(aq) + 2Ag(s)

23. What do you mean by a precipitation reaction? Explain by giving examples.

Answer: A reaction in which an insoluble solid (precipitate) is formed is called a precipitation reaction.

Example: ${\text{Na}}_2{\text{CO}}_3(aq)+{\text{CaCl}}_2(aq)\to {\text{CaCO}}_3(s)\downarrow +2\text{NaCl}(aq)$

24. In this reaction, calcium carbonate is obtained as a precipitate. Hence, it is a precipitation reaction.

Answer:

Another example of precipitation reaction is:

Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s) ↓ + 2NaCl(aq)

Sodium sulphate + Barium chloride → Barium sulphate (precipitate) + Sodium chloride

In this reaction, barium sulphate is obtained as a precipitate.

25. Explain the following in terms of gain or loss of oxygen with two examples of each.

(a) Oxidation

(b) Reduction

Answer:

(a) Oxidation is the gain of oxygen.

For example:

${\text{CO}}_2+{\text{H}}_2\to \text{CO}+{\text{H}}_2\text{O}$

Addition of oxygen - oxidation

$2\text{Cu}+{\text{O}}_2\to 2\text{CuO}$

In equation (i), H₂​ is oxidized to H₂​O and in equation (ii), Cu is oxidised to CuO .

(b) Reduction is the loss of oxygen.

For example,

$C{O}_2+H_2\to CO+H_{2}O$

Removal of oxygen - reduction

(ii) CuO + H₂ →(Δ) Cu + H₂O

Loss of oxygen - reduction

In equation (i), CO₂ is reduced to CO and in equation (ii), CuO is reduced to Cu.

26. A Shiny brown Coloured Element  'X' is copper (Cu) and the black-coloured compound formed is copper oxide (CuO). The equation of the reaction involved in heating  copper is given below.

Answer: 2Cu (Shiny brown) + O₂ →(Heat) 2CuO (Black)

27. Why do we apply paint on iron articles?

Answer: Iron articles are painted because it prevents them from rusting. When painted, the contact of iron articles with moisture and air is cut off. Hence, rusting is prevented. Their presence is essential for rusting to take place.

28. Oil and fat containing food items are flushed with nitrogen. Why?

Answer: Nitrogen is an inert gas and does not easily react with these substances. On the other hand, oxygen reacts with food substances and makes them rancid. Thus, bags used in packing food items are flushed with nitrogen gas to remove oxygen inside the pack. When oxygen is not present inside the pack, rancidity of oil and fat containing food items is prevented.

29. Explain the following terms with one example of each.

(a) Corrosion

(b) Rancidity

Answer:

(a) Corrosion- Corrosion is defined as a process where materials, usually metals, deteriorate as a result of a chemical reaction with air, moisture, chemicals, etc.

For example, iron, in the presence of moisture, reacts with oxygen to form hydrated iron oxide.

4Fe + 3O₂ + nH₂O → 2Fe₂O₃·nH₂O

Hydrated iron oxide

This hydrated iron oxide is rust.

(b) Rancidity - The process of oxidation of fats and oils that can be easily noticed by the change in taste and smell is known as rancidity.

For example, the taste and smell of butter changes when kept for long. Rancidity can be avoided by

(1) Storing food in airtight containers.

(2) Storing food in refrigerators.

(3) Adding antioxidants.

(4) Storing food in an environment of nitrogen.

Exercise - 01

1. For each of the following reactions, determine what the products of each reaction will be? When you have predicted the products, balance the equation.

Assume all reactions take place in water.

(1) AgNO₃ + Na₂CO₃ →

(2) Zn + H₂CO₃ →

(3) MnO₂ + HCl → MnCl₂ + H₂O + Cl₂

(4) FeSO₄ → Fe₂O₃ + SO₂ + SO₃

(5) Pb(NO₃)₂ → PbO + NO₂ + O₂

Multiple Choice Questions

1. Physical changes are generally ________.

(1) temporary

(2) permanent

(3) irreversible

(4) endothermic

2. The symbol H stands for ________ of hydrogen.

(1) one atom

(2) one molecule

(3) one ion

(4) two atoms

3. Which is the correct symbol for manganese?

(1) M

(2) Ma

(3) Mn

(4) Mg

4. The correct formula for nitrogen dioxide is ________.

(1) NO

(2) N₂O

(3) NO₂

(4) N₂O₅

5. Which of the following is an incorrect formula?

(1) NaCl₂

(2) BaSO₄

(3) H₂CO₃

(4) P₂O₅

6. The chemical formula of lead sulphate is

(1) Pb₂SO₄

(2) Pb(SO₄)₂

(3) PbSO₄

(4) Pb₂(SO₄)₃

6. One of the following processes does not involve a chemical reaction. That is:

(1) Melting of candle wax when heated

(2) Burning of candle wax when heated

(3) Digestion of food in our stomach

(4) Ripening of banana

7. The correct formula for ammonium sulphate is ________.

(1) NH₄SO₄

(2) (NH₄)₂SO₄

(3) (NH₃)₂SO₄

(4) (NH₄)₂S

8. In the following equation Na₂CO₃ + x HCl → 2 NaCl + CO₂ + H₂O, the value of x is

(1) 1

(2) 2

(3) 3

(4) 4

9. Consider the reaction: Na(s) + O₂(g) → Na₂O(s). Number of sodium needed to balance the equation would be

(1) 1

(2) 2

(3) 3

(4) 4

10. Consider the reaction: Al(s) + O₂(g) → Al₂O₃. Number of Al(s) needed to balance the equation are

(1) 1

(2) 2

(3) 3

(4) 4

11. It is necessary to balance a chemical equation in order to satisfy the law of

(1) Conservation of motion

(2) Conservation of momentum

(3) Conservation of energy

(4) Conservation of mass

12. The correctly balanced equation for S is ________.

(1) 2FeS + O₂ → Fe₂O₃ + 4SO₂

(2) 2FeS + 3O₂ → 2Fe₂O₃ + 4SO₂

(3) 4FeS + 4O₂ → 2Fe₂O₃ + 2SO₂

(4) 4FeS + 7O₂ → 2Fe₂O₃ + 4SO₂

13. Consider the reaction: S(s) + O₂(g) → SO₂. The state of SO₂ in this reaction is

(1) liquid

(2) solid

(3) gaseous

(4) all of these

14. Which of the following symbols is not a correct indication of the phase of a substance in a reaction?

(1) (s) = solid

(2) (g) = grams

(3) (aq) = aqueous

(4) (ℓ) = liquid

15. The reaction H₂ + Cl₂ → 2HCl is a

(1) decomposition reaction

(2) combination reaction

(3) double displacement reaction

(4) displacement reaction

16. The reaction C + O₂ → CO₂ + Heat, is a

(1) combination reaction

(2) oxidation reaction

(3) exothermic reaction

(4) all of these

17. The electrolytic decomposition of water gives H₂ and O₂ in the ratio of

(1) 1:2 by volume

(2) 2:1 by volume

(3) 8:1 by mass

(4) 1:2 by mass

18. When hydrated ferrous sulphate is heated strongly it undergoes decomposition to form ferric oxide as a main product accompanied by a change in colour from

(1) blue to green.

(2) green to blue.

(3) green to brown.

(4) green to yellow.

19. Breaking of lead bromide into lead and bromine is an example of ________.

(1) decomposition reaction

(2) synthesis reaction

(3) displacement reaction

(4) neutralisation reaction

20. Which of the following is not a decomposition reaction?

(1) CaCO₃ → CaO + CO₂

(2) 2KClO₃ → 2KCl + 3O₂

(3) Digestion of food in the body

(4) H₂ + Cl₂ → 2HCl

21. Which of the following is a decomposition reaction?

(1) NaOH + HCl → NaCl + H₂O

(2) NH₄CNO → H₂NCONH₂

(3) 2KClO₃ → 2KCl + 3O₂

(4) H₂ + I₂ → 2HI

22. Conversion of CaCO₃ into CaO as per the following reaction is an example of

CaCO₃ → CaO + CO₂

(1) decomposition reaction

(2) reduction reaction

(3) oxidation reaction

(4) none of these

23. Which of the following is a displacement reaction?

(1) CaCO₃ → CaO + CO₂

(2) CaO + 2HCl → CaCl₂ + H₂O

(3) Fe + CuSO₄ → FeSO₄ + Cu

(4) NaOH + HCl → NaCl + H₂O

24. Fe₂O₃ + 2Al → Al₂O₃ + 2Fe

This reaction is an example of

(1) combination reaction

(2) double displacement reaction

(3) decomposition reaction

(4) displacement reaction

25. When iron nails are added to an aqueous solution of copper sulphate, a chemical change occurs. Which of the following is not true about this reaction?

(1) The blue colour of the solution fades.

(2) Iron nails become brownish in colour.

(3) It is a displacement reaction.

(4) Iron nails dissolve completely.

26. In the reaction : BaCl₂ + ZnSO₄ → ZnCl₂ + BaSO₄, the white precipitate seen is due to ________.

(1) ZnCl₂

(2) BaSO₄

(3) BaCl₂

(4) ZnSO₄

27. Which of the following represents a double displacement reaction?

(1) 2H₂ + O₂ → 2H₂O

(2) 2Mg + O₂ → 2MgO

(3) AgNO₃ + NaCl → AgCl(↓) + NaNO₃

(4) H₂ + Cl₂ → 2HCl

28. Which of the following reactions is a double displacement reaction?

(1) FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl

(2) Zn + H₂SO₄ → ZnSO₄ + H₂

(3) 2CO + O₂ → 2CO₂

(4) N₂ + O₂ → 2NO

29. Which of the following is a redox reaction?

(1) CaCO₃ → CaO + CO₂

(2) CuO + H₂ → Cu + H₂O

(3) CaO + 2HCl → CaCl₂ + H₂O

(4) NaOH + HCl → NaCl + H₂O

30. Which of the following statements is correct about the reaction?

2PbO(s) + C(s) → 2Pb(s) + CO₂(g)

(1) Lead is getting reduced

(2) Carbon is getting reduced

(3) Lead oxide is getting reduced

(4) All of these

31. Mg + O₂ → MgO which is correct about this reaction?

(1) Mg is oxidized

(2) Oxygen is oxidized

(3) MgO is reduced

(4) MgO is oxidized

32. Corrosion of iron is known as

(1) rusting

(2) rancid

(3) antioxidant

(4) reduction

33. Which of the following gases is used in the storage of fat and oil containing foods for a long time?

(1) Carbon dioxide gas

(2) Nitrogen gas

(3) Oxygen gas

(4) Neon gas

34. The main cause of rancidity in foods is

(1) bacteria

(2) proteins

(3) antioxidants

(4) oxidation of the fatty acid molecule

Fill in the blanks

1. Formation of nitric oxide from nitrogen and oxygen is a ………. reaction.

2. Reaction in which energy is absorbed is known as………. reaction.

3. The reaction in which heat is given out along with products is known as ………. reaction.

4.Digestion of food in our body is an example of ……….reaction.

5. The reaction CaCO₃ →(Heat) CaO + CO₂ is a ………. reaction.

6. The reaction in which oxygen is added to the substance is called ………. reaction.

7. The reaction in which hydrogen is added to a substance is called……... .reaction.

8. The potato chips manufacturers use ………. gas to fill the chips bags to prevent the chips from getting oxidised.

9. When calcium carbonate is heated, it decomposes to give ………. and ………..

10.Rancidity of food is a ………. change.

True or False

1. Rusting of iron is a physical change. 

2. In general, combination reactions are exothermic.

3. A physical change is usually reversible. 

4. When a magnesium ribbon burns brilliantly in air, a physical change takes place. 

5. 3Fe + H₂O → Fe₃O₄ + 4H₂ is a balanced reaction. 

6. Ammonium chloride dissolves in water with the absorption of heat. This is an Exothermic reaction.

7. At least one of the products or reactants must be solid.

8. Iron nails become brownish in copper sulphate solution.

9. Precipitate is an insoluble substance formed during a reaction.

10. If a substance gains oxygen during a reaction, it is said to be, not reduced.

Match the Column

Crossword Puzzle

1. Complete the puzzle using the clues about chemical reactions shown below.

Across

(1) The negatively charged particle of an atom.

(2) An outside agent that affects the speed or occurrence of a reaction.

(3) An expression in which symbols and formulae represent a chemical reaction.

(4) A substance that takes part in a chemical reaction.

Down

(3) Reaction in which energy is liberated.

(5) A substance made up of two or more elements chemically combined.

(6) A chemical process where two substances interact to form a new substance.

(7) The smallest unit of an element.

(8) The center of an atom that contains protons and neutrons.

(9) A new substance produced by a chemical reaction.

(10) A substance made up of one kind of atom; it cannot be broken down into simpler substances.

Answer Key

(1) 2AgNO₃ + Na₂CO₃ → Ag₂CO₃ + 2NaNO₃

(2) Zn + H₂CO₃ → ZnCO₃ + H₂

(3) MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂

(4) 2FeSO₄ → Fe₂O₃ + SO₂ + SO₃

(5) 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂

Multiple choice questions

Fill in the blanks

1. combination
2. endothermic
3. exothermic
4. decomposition
5. decomposition
6. oxidation
7. reduction
8. nitrogen
9. CaO and CO2​
10. chemical

True or False

1. False
2. True
3. True
4. False
5. False
6. False
7. False
8. True
9. True
10. False

Match the column

(A) → (iii), (iv) ; (B) → (i), (ii), (iv) ; (C) → (ii) ; (D) → (i) ; (E) → (v)

Crossword puzzle

Exercise-02

Very short answer type questions

1. Which one is a chemical change: rusting of iron or melting of iron?

2. On what basis is the balancing of a chemical equation done?

3. What happens chemically when quick lime is added to water?

4. Define a combination reaction. Give one example of an exothermic combination reaction.

5. Give one type of decomposition reaction.

6. Give an example of a photochemical reaction.

7. What will happen if silver bromide is kept in sunlight for some time?

8. What happens when a strip of zinc is dipped in a copper sulphate solution?

9. Is copper more reactive than iron? Give a reaction in support of your answer.

10. In which type of reaction does the exchange of ions take place?

11. What is meant by endothermic and exothermic reactions?

12. What is a redox reaction?

13. Identify the type of reaction in the following:

(i) Fe + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

(ii) 2H₂ + O₂ → 2H₂O

14. What is corrosion?

15. Define the term rancidity.

16. Short answer type questions:

17. Which among the following are physical or chemical changes?

(a) Evaporation of petrol

(b) Burning of Liquefied Petroleum Gas (LPG)

(c) Heating of an iron rod to red hot.

(d) Curdling of milk

(e) Sublimation of solid ammonium chloride

18. Balance the following chemical equations and identify the type of chemical reaction.

(a) Mg(s) + Cl₂(g) → MgCl₂(s)

(b) HgO(s) →[Heat] Hg(l) + O₂(g)

(c) Na(s) + S₈(s) →[Fuse] Na₂S(s)

(d) H₂O₂(l) →[uv] H₂O(l) + O₂(g)

19. Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Write the chemical reaction involved and identify the type of reaction.

20. Translate the following reaction into the language of chemistry and then balance it. When ferric oxide is heated with aluminium, it gives aluminium oxide and iron.

21. What are decomposition reactions? Give one example each of:

(a) Thermal decomposition reaction

(b) Electrolytic decomposition

(c) Photolytic decomposition

22. Draw a labelled schematic diagram to show the electrolysis of water. Why is the amount of gas collected in one of the test tubes in this activity double the amount collected in the other?

23. What do you mean by a precipitation reaction?

24. The following reactions are observed to occur:

(i) CuSO₄ + Fe → FeSO₄ + Cu

(ii) FeSO₄ + Zn → ZnSO₄ + Fe

(iii) 2AgNO₃ + Cu → Cu(NO₃)₂ + 2Ag

Arrange Cu, Fe, Ag and Zn in order of their reactivity.

25. A solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction?

26. What happens when an iron nail is put inside a copper sulphate solution? Write the reactions with observations.

27. Define oxidation and reduction. In the following reactions, identify which one is reduced and which one is oxidized?

MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂

28. What do you mean by a precipitation reaction?

29. Give two examples from everyday life situations where redox reactions are taking place.

30. Identify the substances oxidized and reduced in the following reaction.

ZnO + C → Zn + CO

31. What type of chemical reaction takes place when:

(i) Magnesium wire is burnt in air.

(ii) Electric current passed through water.

(iii) Limestone is heated.

(iv) Digestion of food occurs in the body.

(v) Ammonia and hydrogen chloride gases are mixed.

(vi) Sulphuric acid is added into barium chloride solution.

Long answer type questions

1. A magnesium ribbon is burnt in oxygen to give a white compound X accompanied by emission of light. If the burning ribbon is now placed in an atmosphere of nitrogen, it continues to burn and forms a compound Y.

(a) Write the chemical formulae of X and Y.

(b) Write a balanced chemical equation, when X is dissolved in water.

2. On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.

(a) Write a balanced chemical equation of the reaction.

(b) Identify the brown gas X evolved.

(c) Identify the type of reaction.

(d) What could be the pH range of aqueous solution of the gas X ?

3. What are the rules for balancing a chemical equation? Explain with suitable examples.

4. What is a combination reaction? Explain with suitable examples.

5. When CaO is added to water taken in a beaker, rise in temperature is observed. However, when Ba(OH)2 is mixed with NH4Cl, a fall in temperature is observed. Why?

6. What are the differences between displacement and double displacement reactions? Explain with suitable examples.

7. What happens when a piece of

(a) Iron metal is added to copper sulphate solution?

(b) Aluminium metal is added to dilute hydrochloric acid?

(c) Silver metal is added to copper sulphate solution?

Also, write the balanced chemical equation if the reaction occurs.

8. On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained.

(a) Write a balanced chemical equation of the reaction involved.

(b) What other name can be given to this precipitation reaction?

(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?

(a) Observe the given figure and answer the following questions.

(i) Write the complete balanced chemical equation for the above reaction.

(ii) What is the type of reaction involved?

(iii) Is there any precipitate formed?

(iv) If any precipitate is formed then write the colour of the precipitate.

(b) When a water insoluble substance 'X' is added to dilute hydrochloric acid, a colourless and odourless gas is evolved. When this gas is passed through lime water, it turns milky. The compound X is regained. Write the chemical formula of 'X' and the chemical equations involved.

What is oxidation and reduction? Taking suitable examples, explain that oxidation and reduction always take place together.

Exercise-01 (Solutions)

Multiple choice questions

1. Option (1)

Physical changes are those which can generally be converted back into their original state, so they are temporary.

2. Option (1)

H stands for an atom of hydrogen.

3. Option (3)

The correct symbol for manganese is Mn.

4. Option (3)

Nitrogen dioxide NO2 (di means two).

5. Option (1)

6. Option (3)

PbSO4 - Lead sulphate.

7. Option (1)

Melting of wax is a physical change.

8. Option (2)

(NH4)2SO4

9. Option (2)

Na2CO3 + 2HCl → 2NaCl + CO2 + H2O

10. Option (4)

4Na + O2 → 2Na2O

11. Option (4)

4Al + 3O2 → 2Al2O3

12. Option (4)

To satisfy the law of conservation of mass.

13. Option (4)

4FeS + 7O2 → 2Fe2O3 + 4SO2

14. Option (3)

S(s) + O2(g) → SO2(g)

15. Option (2)

'g' represents the gaseous state of a substance.

16. Option (2)

The reactions in which two or more substances combine to form a single new substance are called combination reactions.

H2 + Cl2 → 2HCl is a combination reaction.

17. Option (4)

C + O2 → CO2 is a combination reaction as well as an oxidation reaction which produces heat.

18. Option (2)

2H2O → 2H2 + O2 (2vol. : 2vol. : 1vol.)

19. Option (3)

2FeSO4 → Fe2O3 + SO2 + SO3 (Green : Brown)

20. Option (1)

The reaction in which a single compound breaks up into two or more simpler substances is known as a decomposition reaction.

2PbBr2 → 2Pb + 2Br2 is a decomposition reaction.

21. Option (4)

The reactions in which two or more substances combine to form a single new substance are called combination reactions. It is not a decomposition reaction.

H2 + Cl2 → 2HCl is a combination reaction.

22. Option (3)

The reaction in which a single compound breaks up into two or more simpler substances is known as a decomposition reaction.

2KClO3 → 2KCl + 3O2 (Heat)

23. Option (1)

The reaction in which a single compound breaks up into two or more simpler substances is known as a decomposition reaction.

CaCO3 → CaO + CO2 (Heat)

24. Option (3)

A reaction in which a more reactive element displaces a less reactive element from its compounds is called a displacement reaction. Iron is more reactive than Cu so it can displace the Cu from its compound.

Fe + CuSO4 → FeSO4 + Cu

25. Option (4)

A reaction in which a more reactive element displaces a less reactive element from its compounds is called a displacement reaction. It is also an example of a displacement reaction.

26. Option (4)

Iron displaces copper from copper sulphate solution forming iron (II) sulphate in the solution, which has a light green colour. Hence, the blue colour of copper sulphate solution fades. The displaced copper is deposited on the iron nail giving it a brownish colour.

Fe + CuSO4 → FeSO4 + Cu

27. Option (2)

Barium chloride solution reacts with zinc sulphate solution to form a white precipitate of barium sulphate along with zinc chloride in the solution.

BaCl2 + ZnSO4 → ZnCl2 + BaSO4 (White PPt.)

28. Option (3)

Those reactions in which two different atoms or groups of atoms are exchanged are called double displacement reactions.

NaCl + AgNO3 → AgCl + NaNO3 (it is an example of a double displacement reaction)

29. Option (1)

Those reactions in which two different atoms or groups of atoms are exchanged are called double displacement reactions.

FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl

30. Option (2)

CuO is getting reduced while H2 is getting oxidized.

31. Option (3)

A substance which gives oxygen or gains hydrogen (reduced) is called an oxidizing agent whereas a substance which gives hydrogen or gains oxygen (oxidized) is called a reducing agent.

32. Option (1)

A substance which gives oxygen or gains hydrogen (reduced) is called an oxidizing agent whereas a substance which gives hydrogen or gains oxygen (oxidized) is called a reducing agent.

33. Option (1)

Corrosion of iron is known as rusting.

34. Option (2)

Nitrogen gas is used in the storage of fat and oil containing foods for a long time.

35. Option (4)

The oxidation of oils or fats in food, resulting in bad taste and bad smell, is called rancidity.

True or false

1. False

In a chemical change one or more substances change into new substances. So rusting of iron is a chemical change.

2. True

Combination reactions produce heat, so they are usually exothermic in nature.

3.True

Physical changes are usually reversible.

4. False

Combustion of magnesium metal is a chemical change.

5. False

3Fe + 4H2O → Fe3O4 + 4H2

6. False

Dissolution of NH4Cl in water is an endothermic reaction.

7. False

Products or reactants can be in any physical state.

$\text{Fe}(\text{Greyish black})+{\text{CuSO}}_4\to {\text{FeSO}}_4+\text{Cu}(\text{Reddish brown})$

8. True

Precipitate is an insoluble substance formed during reaction.

9. False

If a substance gains oxygen during reaction, it is said to be oxidized.

Exercise-02 (Solutions)

Very short answer type questions

1. A chemical change in which one or more substances change into new substances, so rusting of iron is a chemical change.

2. According to the law of conservation of mass, the total mass of products must be equal to the total mass of the reactants. That's why a balancing of a chemical equation is done.

3. CaO + H₂O → Ca(OH)₂

   (Calcium oxide (Quick lime)) + (Water) → (Calcium hydroxide (slaked lime))

4. When two or more substances react together to form a single product, the reaction is called a combination reaction.

   C + O₂ → CO₂ + Heat

5. CaCO₃ → CaO + CO₂ [Thermal decomposition]

6. AgCl → Ag + Cl₂

   Silver bromide decomposes into grey silver and bromine in the presence of light.

   2AgBr(s) → 2Ag(s) + Br₂(g)

7. Zinc displaces copper from copper sulphate solution forming zinc(II) sulphate in the solution, which is colorless. Hence, the blue color of copper sulphate solution fades. The displaced copper is deposited on the zinc strip giving it a brownish color.

   Zn + CuSO₄ → ZnSO₄ + Cu

8. No, iron is more reactive than copper. A reaction in which a more reactive element displaces a less reactive element from its compounds is called a displacement reaction. Iron can displace copper from copper sulphate solution forming iron(II) sulphate in the solution, so copper is less reactive than iron.

   Fe + CuSO₄ → FeSO₄ + Cu

9. In a double displacement reaction, exchange of ions takes place.

   HCl + NaOH → NaCl + H₂O

10. The reaction which occurs by absorbing heat energy is called an endothermic reaction.

    E.g. CaCO₃ → CaO + CO₂

11. The reaction which occurs by releasing heat energy is called an exothermic reaction.

    E.g. C + O₂ → CO₂ + Heat

12. A chemical reaction in which both oxidation and reduction take place simultaneously is known as a redox reaction.

    E.g. Zn + CuSO₄ → ZnSO₄ + Cu

13. (i) Displacement reaction

    (ii) Combination reaction

14. The chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties is called corrosion.

15. The oxidation of oils or fats, resulting in a bad taste and bad smell, is called rancidity.

Short answer type questions

1. (a), (c), (e) are physical changes and (b), (d) are chemical changes.

2. (a) Mg(s) + Cl₂(g) → MgCl₂(s); Combination reaction

   (b) 2HgO(s) → 2Hg(l) + O₂(g); Decomposition reaction

   (c) 16Na(s) + S₈(s) → 8Na₂S(s); Combination reaction

   (d) 2H₂O₂(l) → 2H₂O(l) + O₂(g); Decomposition reaction

3. FeSO₄.7H₂O → FeSO₄ + 7H₂O

   2FeSO₄ → Fe₂O₃ + SO₂ + SO₃ (Decomposition reaction)

   It is observed that green colored ferrous sulphate crystals on heating first change color by losing water to form FeSO₄, which on further heating decomposes to leave behind a reddish-brown residue along with the evolution of sulphur dioxide and sulphur trioxide gases.

4. Fe₂O₃ + 2Al → Al₂O₃ + 2Fe; Redox reaction, Single displacement reaction

5. When a single substance breaks into two or more simpler substances by the action of some form of energy, the reaction is called a decomposition reaction.

   (a) CaCO₃ → CaO + CO₂

   (b) H₂O → H₂ + O₂

   (c) AgCl → Ag + Cl₂

6. Acidified water undergoes electrolysis producing H₂ and O₂ gases in the ratio of 2:1 by volume, because water compound has double atoms of hydrogen than oxygen.

Electrolysis of Water

7. BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s)↓ + 2NaCl(aq)

(white ppt)

The above reaction is a double displacement reaction as well as a precipitation reaction.

In the above reaction, an insoluble compound, BaSO₄, is formed because of the double displacement reaction. This type of double displacement reaction where precipitate formation takes place is called a precipitation reaction.

8. (i) CuSO₄ + Fe → FeSO₄ + Cu [Fe > Cu]

(ii) FeSO₄ + Zn → ZnSO₄ + Fe [Zn > Fe]

(iii) 2AgNO₃ + Cu → Cu(NO₃)₂ + 2Ag [Cu > Ag]

So, the order of reactivity is Ag < Cu < Fe < Zn.

9. KCl(aq) + AgNO₃(aq) → AgCl(s) + KNO₃(aq)

Double displacement reaction or precipitation reaction.

10. Iron displaces copper from copper sulphate solution forming iron(II) sulphate in the solution, which has a light green colour. Hence, the blue colour of copper sulphate solution fades. The displaced copper is deposited on the iron nail giving it a brownish colour.

Fe + CuSO₄ → FeSO₄ + Cu

11. The reaction which involves the addition of oxygen or removal of hydrogen from a substance is called an oxidation reaction. The reaction which involves the addition of hydrogen or removal of oxygen from a substance is called a reduction reaction.

MnO₂ is reduced; and HCl is oxidized.

12. Copper displaces silver from silver nitrate solution to form copper nitrate in the solution, which has a blue colour. Hence, the silver nitrate solution becomes blue in colour after some time, when copper turnings are added to it. The displaced silver is deposited on the copper turnings giving it a silvery grey colour.

Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

13. Combustion, photosynthesis, respiration, etc., are examples of everyday redox reactions.

14. ZnO - reduced substance

C - oxidized substance.

15. (i) Combination reaction

(ii) Decomposition reaction

(iii) Decomposition reaction

(iv) Decomposition reaction

(v) Combination reaction

(vi) Double displacement (precipitation) reaction

Long answer type questions

1. (a) X = MgO, Y = Mg₃N₂

(b) MgO + H₂O → Mg(OH)₂

2. (a) 2Cu(NO₃)₂ → 2CuO + 4NO₂ + O₂

(copper nitrate (blue)) (copper oxide (black)) (nitrogen dioxide (brown fumes))

(b) NO₂ = Brown gas

(c) Thermal decomposition reaction

(d) It is acidic in nature, so the pH range will be between 0-7.

3. Steam is passed over red hot iron to form Iron (II, III) oxide and hydrogen in the presence of air.

Step-I : Iron + Steam → Iron (II, III) Oxide + Hydrogen

Step-II : Fe + H₂O → Fe₃O₄ + H₂

Step-III :

Fe + H₂O → Fe₃O₄ + H₂

Step-IV : Formula selected is Fe₃O₄ to start balancing oxygen.

(i) To balance O-atoms, multiply H₂O in LHS by 4.

Fe + 4H₂O → Fe₃O₄ + H₂

(ii) Now balance Fe atoms.

3Fe + 4H₂O → Fe₃O₄ + H₂

(iii) Balance H atoms.

3Fe + 4H₂O → Fe₃O₄ + 4H₂

Note: Mixture of ferrous oxide (FeO) and ferric oxide (Fe₂O₃) is also known as magnetic oxide of iron.

Step-V : On checking the number of all elements, we found that the equation is balanced now.

3Fe + 4H₂O → Fe₃O₄ + 4H₂

4. When two or more substances react together to form a single product, the reaction is called a combination reaction.

E.g. C + O₂ → CO₂ + Heat

CaO + CO₂ → CaCO₃

N₂ + 3H₂ → 2NH₃

5.  The chemical reaction between Calcium Oxide (CaO) and water (H₂O) is an exothermic reaction. This means it releases heat, causing the temperature of the solution to increase.

Equation: CaO + H₂O → Ca(OH)₂ + heat

The chemical reaction between Barium Hydroxide (Ba(OH)₂) and Ammonium Chloride (NH₄Cl) is an endothermic reaction. This means it absorbs heat from the surrounding solution, causing the temperature to decrease.

Equation: Ba(OH)₂ + NH₄Cl → BaCl₂ + NH₄OH (heat is absorbed)

6. 

7. (a) Iron and Copper Sulphate:

Iron (Fe) displaces copper (Cu) from copper sulphate (CuSO₄) solution, forming iron(II) sulphate (FeSO₄).

The blue colour of the copper sulphate solution fades, and the solution turns light green due to the formation of iron(II) sulphate.

The displaced copper is deposited on the iron nail, giving it a brownish colour. 

Equation: Fe + CuSO₄ → FeSO₄ + Cu

(b) Aluminum and Hydrochloric Acid:

When aluminum (Al) metal is added to dilute hydrochloric acid (HCl), hydrogen gas (H₂) is liberated, and aluminum chloride (AlCl₃) is formed.

Equation: 2Al + 6HCl -> 2AlCl3 + 3H2

(c) Barium Chloride and Sodium Sulphite:

BaCl₂ + Na₂SO₃ → 2NaCl + BaSO₃ (white precipitate)

On adding hydrochloric acid to the reaction mixture, the white precipitate disappears because it reacts with barium sulphite and forms barium chloride.

BaSO₃ + 2HCl → BaCl₂ + H₂SO₃

8. (a) Sodium Sulphate and Barium Chloride:

Na₂SO₄ + BaCl₂ → 2NaCl + BaSO₄ (white precipitate)

This is a double displacement or precipitation reaction.

A white precipitate of BaSO₄ is formed.

(b) Calcium Carbonate and Hydrochloric Acid:

Chemical formula of X: CaCO₃

CaCO₃ + 2HCl → CaCl₂ + CO₂ (colourless gas) + H₂O

CO₂ + Ca(OH)₂ (lime water) → CaCO₃ (milkiness) + H₂O

9. Oxidation Reaction:

A reaction that involves the addition of oxygen or the removal of hydrogen from a substance.

Reduction Reaction:

A reaction that involves the addition of hydrogen or the removal of oxygen from a substance.

$\text{ZnO + C}\stackrel{\text{Heat}}{\to }\text{Zn + CO}$

ZnO : Oxidizing agent

C : Reducing agent

Oxidation and Reduction in Terms of Electronic Concept

Aim: To study the oxidation of copper to copper (II) oxide.

Materials Required:

China dish

Copper powder (approximately 1g)

Burner

Tripod stand

Wire gauze

Method:

1.  Place approximately 1 gram of copper powder in a China dish.

2.  Heat the China dish using a burner, supported by a tripod stand and wire gauze.

Observation:

The brown copper powder is observed to be coated with a black substance, which is copper (II) oxide.

Conclusion:

Copper (brown in color) when heated, combines with oxygen from the air to form black copper (II) oxide.

Chemical Equation:

2Cu(s) + O₂(g) → 2CuO(s)

Where:

Cu(s) represents copper (solid, brown)

O₂(g) represents oxygen (gas)

CuO(s) represents copper (II) oxide (solid, black)

In this reaction, copper is said to be oxidized because it gains oxygen.

${\text{CuO + H}}_2\stackrel{\text{Heat}}{\to }{\text{Cu + H}}_2\text{O}$

Such reactions where both oxidation and reduction reactions take place are called oxidation- reduction reactions or redox reactions.

5.0Benefits of Studying Class 10 Science Chapter 1 Chemical Reactions And Equations

Studying Class 10 Science Chapter 1, "Chemical Reactions and Equations," offers several benefits that lay a strong foundation for understanding chemistry and its real-world applications. Here are some key advantages:

1. Builds a Strong Foundation: This chapter introduces fundamental concepts of chemistry, such as chemical reactions and equations, which are essential for understanding more advanced topics in higher classes.
2. Enhances Problem-Solving Skills: By learning to balance chemical equations and predict the outcomes of various reactions, students improve their analytical and problem-solving abilities, which are crucial for tackling complex problems in future studies.
3. Understanding Everyday Phenomena: The chapter explains common processes like corrosion and rancidity, helping students relate classroom learning to real-life situations, such as rusting of iron or spoilage of food.
4. Improves Scientific Literacy: Familiarity with chemical symbols, equations, and reaction types enhances students' scientific literacy, enabling them to comprehend scientific articles, experiments, and discussions more effectively.
5. Prepares for Competitive Exams: The concepts covered in this chapter are foundational for competitive exams like NTSE and Olympiads. A strong grasp of these topics can give students an edge in such assessments.
6. Develops Critical Thinking: Understanding different types of chemical reactions and their characteristics fosters critical thinking. Students learn to classify reactions, predict products, and understand reaction mechanisms.
7. Facilitates Conceptual Clarity: The chapter provides clear explanations of various reaction types and balancing equations, helping students overcome common misconceptions and develop a solid conceptual base.
8. Encourages Curiosity and Experimentation: By learning about different reactions and their outcomes, students are encouraged to explore and experiment with safe, simple reactions at home or in the lab, fostering a deeper interest in science.