NCERT Solutions for class 10 Science Chapter 1 chemical reactions and equations includes all the essential topics with detailed explanations to help students to comprehend the concepts better. If you are preparing for your Class 10 exams, NCERT Solutions for Science Chapter 1 Chemical Reactions and Equations will help you to revise the complete syllabus and score higher marks in your exams. NCERT Solution for Class 10 Science Chapter 1 Chemical reactions and equations will also help you to solve your Homework and Assignments in a timely manner.
You can download the NCERT Solution for Class 10 Science Chapter 1 Chemistry Reactions and Equations PDF to access it even offline mode. You will also get access to all the free study materials and solutions, as well as absolutely free online tests to improve your problem-solving speed.
The NCERT solutions for class 10 science Chapter 1 – Chemical Reactions and Equations are created by our experts in class 10 science in an easy-to-understand way.
NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations
NCERT solutions for Class 10 science chapter 1 chemical reactions and equations are available to help students prepare for their exams. Students can use NCERT solutions for all Chapter 1 – Chemical reactions and equations exercise questions to revise the syllabus and score higher marks in their examinations. Students can also download NCERT Solution for Class 10 science to revise the complete syllabus. NCERT solutions will also help students to solve their homework and assignments on time.
Students can download NCERT solutions for class 10 science chapter 1 chemical reactions and equations Notes PDF even offline mode. Students will have access to all free study materials and solutions as well as absolutely free online tests to improve their problem solving speed.
The NCERT solutions for Class 10 science chapter 1 – chemical reactions and equations provided here are designed by the subject matter experts in an easy-to-understand way.
Before we get into the details of the NCERT Solutions For class 10 science Chapter 1 chemical reactions and Equations, here is a list of some of the topics and sub-topics under the Class 10 science Chapter 1 Chemical reactions and Equations.
These topics include chemical reactions, chemical equations, and types of chemical reactions.
Have you observed the effects of oxidation reactions in your everyday life?
Download NCERT Solutions for Chapter 1 Chemical Reactions and Equations PDF for Class 10 Science for free download in Hindi Medium and English Medium for Students of CBSE Class 10, Uttarakhand Class 10, Bihar Class 10, Madhya Pradesh Class 10, Gujarat Class 10, UP Class 10 Students using NCERT books based on the updated CBSE syllabus for session 2019-20.
NCERT Solutions for Class 10 Science Chapter 1Question Solutions
Question 1
Which of the statements about the reaction below are incorrect?
2 PbO(s) + C(s) → 2Pb (s) + CO2(g)
(a) Lead is getting reduced.
(b) Carbon dioxide is getting oxidised.
(c) Carbon is getting oxidised.
(d) Lead oxide is getting reduced.
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) All
Answer:
(i) (a) and (b)
Question 2
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) Displacement reaction.
Question 3
What happens when dilute hydrochloric acid is added to iron fillings? 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.
Question 4
What is a balanced chemical equation? Why should chemical equations be balanced?
Answer:
A balanced chemical equation is one where the number of atoms of each element on both the reactant and product sides is the same. Chemical equations should be balanced to obey the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Balancing equations ensures that the same number of atoms of each element are present on both sides of the equation, thus maintaining mass equilibrium.
Question 5
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in the air to give water and sulphur dioxide.
(c) Barium chloride reacts with aluminum sulphate to give aluminum chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Answer:
(a) 3H2 (g) + N2 (g) → 2NH3 (g)
(b) H2S (g) + 3O2 (g) → SO2 (g) + 2H2O(l)
(c) 3BaCl2 (aq) + Al2(SO4)3 (aq) → 2AlCl3 (aq) + 3BaSO4 ↓(s)
(d) 2K (s) + 2H2O (l) → 2KOH (aq) + H2 (g)
Question 6
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
Question 7
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) Aluminium + Copper chloride → Aluminium chloride + Copper
(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride
Answer:
(a) Ca (OH)2 + CO2 → CaCO3 + H2O
(b) Zn + 2AgNO3 → Zn(NO3)2 + 2 Ag
(c) 2Al + 3 CuCl2 → 2AlCl3 + 3 Cu
(d) BaCl2 + K2SO4 → BaSO4 + 2KCl
Question 8
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
(b) Zinc carbonate(s) → Zinc oxide (s) + Carbon dioxide (g) bromide(s)
(c) Hydrogen (g) + Chloride (g) → Hydrogen chloride (g)
(d) Magnesium (s) + Hydrochloric acid (aq) → Magnesium chloride (aq) + Hydrogen (g)
Answer:
(a) 2KBr (aq) + Bal2(aq) → 2Kl(aq) + BaBr2(s)
Type: Double displacement reaction
(b) ZnCO3 (s) → ZnO (s) + CO2 (g)
Type: Decomposition reaction
(c) H2 (g) + Cl2 (g) → 2HCl(g)
Type: Combination reaction
(d) Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
Type: Displacement reaction
Question 9
What does one mean by exothermic and endothermic reactions? Give examples.
Answer:
Exothermic reactions release heat energy to the surroundings. Examples include combustion reactions, such as the burning of wood or gasoline.
Example :
(i) C (s) + O2 (g) → CO2 (g) + Heat
(ii) N2 (g) + 3H2 (g) → 2NH3 (g) + Heat
Endothermic reactions absorb heat energy from the surroundings. An example is the process of photosynthesis in plants.
Examples :
(i) C (s) + 2S (s) → CS2 (l) – Heat
(ii) N2 (g) + O2 (g) → 2NO(g) – Heat
Question 10
Why is respiration considered an exothermic reaction? Explain.
Answer:
Respiration is considered exothermic because it involves the breakdown of glucose in living organisms to produce energy in the form of ATP (adenosine triphosphate) while releasing heat energy as a byproduct. The chemical reactions involved in respiration are exothermic and release energy for the organism’s metabolic processes.
Question 11
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Answer:
Decomposition reactions involve breaking down a compound into its constituent elements or simpler compounds. They are called the opposite of combination reactions because in combination reactions, elements or simpler compounds combine to form a more complex compound.
Decomposition of water:
Decomposition of hydrogen peroxide:
Question 12
Write one equation each for the decomposition reactions where energy is supplied in the form of heat, light or electricity.
OR
Decomposition reactions require energy either in the form of heat light or electricity to break down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity.
Answer:
Question 13
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
Answer:
In displacement reactions, a more reactive metal displaces a less reactive metal from its solution. For example,
Fe(s) + CuSO4(aq) → Cu(s) + FeSO4(aq)
This is a displacement reaction where iron displaces copper from its solution.
In double displacement reactions, two reactants in solution exchange their ions. For example,
AgNO3(aq) + NaCl (aq) → AgCl(s) + NaNO3 (aq)
This is a double displacement reaction where silver nitrate and sodium chloride exchange Cl– and NO3– ions between them.
Question 14
In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
Answer:
Question 15
What do you mean by a precipitation reaction? Explain by giving examples.
Answer:
A reaction in which an insoluble solid called a precipitate is formed that separates from the solution is called a precipitation reaction.
Example: When a solution of iron (III) chloride and ammonium hydroxide is mixed, a brown precipitate of iron (III) hydroxide is formed.
Question 16
Explain the following in terms of gain or loss of oxygen with two examples each:
(a) Oxidation and
(b) Reduction.
Answer:
(a) Oxidation: The addition of oxygen to a substance is called oxidation.
Example :
(i) S(s) + O2(g) → SO2(g) (Addition of oxygen to sulphur)
(ii) 2Mg(s) + O2 (g) → 2MgO(s) (Addition of oxygen to magnesium)
(b) Reduction: The removal of oxygen from a substance is called reduction.
Example: (i) CuO + H2 Heat−→ Cu + H2O
Here, copper oxide is being reduced to copper because oxygen gets removed from copper oxide.
(ii) ZnO + C → Zn + CO
Here, zinc oxide is being reduced to zinc because oxygen gets removed from zinc oxide.
Question 17
A shiny brown coloured element ‘X’ on heating in the air becomes black in colour. Name the element ‘X’ and the black-coloured compound formed.
Answer:
Element ‘X’ is copper (Cu).
The black-coloured compound is copper oxide (CuO). The reaction involved is
Question 18
Why do we apply paint on iron articles?
Answer:
Paint does not allow iron articles to come in contact with air, or water and saves iron articles from damage due to rusting.
Question 19
Oil and fat-containing food items are flushed with nitrogen. Why?
Answer:
To keep food items fresh and save them from getting oxidized, food items are flushed with nitrogen.
Question 20
Explain the following terms with one example each (a) Corrosion, (b) Rancidity.
Answer:
(a) Corrosion: It is the process in which metals are eaten up gradually by the action of air, moisture or a chemical (such as an acid) on their surface.
Example: When iron is exposed to moist air for a long period of time, its surface acquires a coating of a brown, flaky substance called rust. Rust is mainly hydrated iron (III) oxide [Fe2O3.xH20].
(b) Rancidity: The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called rancidity.
Rancidity spoils the food materials prepared in fats and oils which have been kept for a considerable time and makes them unfit for eating.
Rancidity can be prevented by adding anti-oxidants to foods containing fats and oils. It can also be prevented by flushing fat and oil-containing foods with nitrogen before sealing.
NCERT Solutions for Class 10 Science Chapter 1 Activities Questions
Page No: 6
Question1
Why should a magnesium ribbon be cleaned before burning in air?
Answer:
A magnesium ribbon should be cleaned before burning in the air to remove any oxide layer that may have formed on its surface. Magnesium can react with oxygen in the air to form a protective layer of magnesium oxide (MgO). This layer can inhibit the reaction when you want to burn magnesium in the air. Cleaning the magnesium ribbon by scraping the oxide layer off exposes the fresh, reactive magnesium metal, allowing it to readily react with oxygen when ignited.
Question 2
Write the balanced equation for the following chemical reactions:
Answer:
(i) Hydrogen + Chlorine → Hydrogen chloride
H2(g) + Cl2(g) → 2HCl(g)
(ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3BaCl2(aq) + Al2(SO4)3(aq) → 3BaSO4(s) + 2AlCl3(aq)
(iii) Sodium + Water → Sodium hydroxide + Hydrogen
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
Question 3
Write a balanced chemical equation with state symbols for the following reactions:
Answer:
(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaCl(aq)
(ii) Sodium hydroxide solution (in water) reacts with a hydrochloric acid solution (in water) to produce sodium chloride solution and water.
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
In these equations, (aq) represents an aqueous solution, (s) denotes a solid, and (l) signifies a liquid.
Page No: 10
Question 1
Solution for Substance ‘X’ used for Whitewashing:
Answer:
(i) The substance ‘X’ used for whitewashing is Calcium Oxide, which is also known as Quicklime. Its chemical formula is CaO.
(ii) The reaction of calcium oxide (CaO) with water (H2O) is highly exothermic and produces calcium hydroxide (Ca(OH)2):
CaO(s) + H2O(l) → Ca(OH)2(aq)
Question 2
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
Answer:
This observation is likely due to the fact that the reaction in one of the test tubes involves a compound that contains two moles of the gas being collected, whereas the other test tube involves a compound with only one mole of the gas.
For example, if one of the reactions involves the decomposition of calcium carbonate (CaCO3), it will produce one mole of carbon dioxide (CO2) gas:
CaCO3(s) → CaO(s) + CO2(g)
Meanwhile, if the other reaction involves the decomposition of a compound like hydrogen carbonate (bicarbonate), it will produce two moles of carbon dioxide gas:
2HCO3^-(aq) → 2CO2(g) + 2OH^-(aq) + H2O(l)
In this case, the amount of gas collected in the second test tube would be double compared to the first one.
So, the gas collected is Carbon Dioxide (CO2).
Page No: 13
Question 1
Why does the color of copper sulfate solution change when an iron nail is dipped in it?
Answer:
When an iron nail is dipped into a copper sulfate (CuSO4) solution, a redox (reduction-oxidation) reaction occurs. The iron in the nail displaces the copper in the copper sulfate, leading to the formation of iron sulfate and elemental copper. The color change is due to the production of copper metal, which has a reddish-brown color, in the solution.
Question 2
Give an example of a double displacement reaction other than the one given in Activity 1.10.
Answer:
Another example of a double displacement reaction is the reaction between sodium carbonate (Na2CO3) and hydrochloric acid (HCl) to form sodium chloride (NaCl), carbon dioxide (CO2), and water (H2O):
Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l)
In this reaction, the positive ions (sodium and hydrogen) and the negative ions (carbonate and chloride) exchange partners, leading to the formation of new compounds.
Question 3
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) 4Na(s) + O2(g) → 2Na2O(s)
In this reaction, sodium (Na) is oxidized, and oxygen (O2) is reduced. Sodium loses electrons to form Na2O, while oxygen gains those electrons.
(ii) CuO(s) + H2(g) → Cu(s) + H2O(l)
In this reaction, copper oxide (CuO) is reduced, and hydrogen gas (H2) is oxidized. Copper gains electrons to form copper metal (Cu), while hydrogen loses electrons to form water (H2O).
Oxidation involves the loss of electrons, while reduction involves the gain of electrons. You can remember this using the acronym “OIL RIG,” which stands for “Oxidation Is Loss, Reduction Is Gain.”