Chemical reaction and equation class 10 notes and Question answer

Chemistry Chapter-1 Chemical reaction and equation class 10 pdf notes and essential questions answer

CBSE has made it clear in their latest released syllabus that experiment learning should be used to learn concepts.

Chemical Reaction and Equation Class 10 chapter includes the topic:-chemical equation, balanced chemical equation, the implication of a balanced equation, types of chemical reaction- combination, decomposition, displacement, double displacement, precipitation, endothermic, exothermic reaction, oxidation, and reduction

Topic Notes

  • Chemical reaction
  • Chemical Equation
  • Types of chemical reaction
  • Effect of Oxidation Reaction in Daily Life


Previous Year Questions of chemical Reaction and Equation Class 10

Q.In which of the following, a chemical reaction has take place?

a) Ice melt in to water

b) A wet shirt got dried in sunlight

c) A brown layer is formed on iron rod kept in air

    Show Answer

    Ans-A brown layer is formed on iron rod kept in air

    Show Answer

    Ans-formation of crystal

    Q. Which of the following condition help to us to determine that a chemical reaction has taken place?

    a) Evolution of gas

    b) Formation of precipitate

    c) Change in colour

    Show Answer

    Ans- all of these

    Q. Magnesium ribbon is rubbed before burning because it has a coating of –

    a) Magnesium oxide

    b) Magnesium carbonate

    C) Magnesium sulphate

    Show Answer

    Ans- magnesium oxide

    Q.If magnesium is gently heated, it forms-

    a) Magnesium oxide

    b)Magnesium carbonate

    c) Magnesium sulphate

    Show Answer

    Ans- magnesium oxide

    Q.Reaction of magnesium with air is –

    a) Exothermic

    b) Endothermic

    c) Reversible

    Show Answer

    Ans- exothermic

    Q. Which of the following is physical change?

    a) Formation of curd from milk

    b) Getting salt from sea water

    c) Ripening of fruits

    Show Answer

    Ans- getting salt from sea water

    Q. Which of the following is not a physical change?

    a) Boiling of Water

    b) Melting of ice

    c) Combustion of LPG

    Ans- combustion of LPG

    Show Answer

    Ans- combustion of LPG

    Q. When magnesium ribbon is burnt in air, the ash formed is ——– in colour?

    a) White

    b) Yellow

    c) Grey

    d) Black

    Show Answer

    Ans- white

    Q. Which of the following process involve chemical reaction?

    a) Storing of oxygen gas in cylinder

    b) Liquefaction of air

    c) Heating of copper wire

    Show Answer

    Ans- heating of copper wire

    Chemical Reaction and equation class 10 Test-paper-1

    Q.A process employed for the concentration of sulphide ore is______

    Q.The slag obtained during the extraction of copper pyrites is composed mainly of_____.

    Q. In an electrolytic cell where electrolysis is carried, anode has:_____Charge?

    Q.In the reaction PbO + C → Pb + CO, carbon act as ____agent.

    Q.A substance which oxidizes itself and reduces other is known as____.

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

    Q.Why a combustion reaction an oxidation reaction?

    Q.Why are food particle preferably packed in aluminum foil?

    Q.What happens to lime water when CO2 gas is bubbled through it in excess?

    Q.A student dropped few pieces of marble in dilute hydrochloric acid contained in a test tube. The evolved gas was then passed through lime water. What change would be observed in lime water? Write balanced chemical equation for both the change observed?

    Q.Give one example each of-
    (1) Thermal decomposition
    (2) Electrolytic decomposition
    (3) Photo decomposition

    Chemical Reaction and equation class 10 Test-paper-2

    Q.Some crystals of copper sulphate were dissolved in water. The colour of the solution obtained would be__?

    Q.When dilute HCl is added to zinc pieces taken in a test tube, then__

    Q.PbS reacts with ozone (O3) and forms PbSO4 . As per the balanced equation, molecules of ozone required for every one molecule of PbS is / are

    Q.Chemically rust is__________?

    Q.Identify the type of chemical reaction
    (i) A → B +C
    (ii) AD +CD → AD +CB

    Q. Why does not silver evolve hydrogen on reacting with dil H2SO4

    Q.Way do diamond and graphite, the two allotropic forms of carbon evolve different amounts of heat on combustion?

    Q.What is the role of oxidizing agent is a reaction?

    Q.Write the balanced reactions for the following
    (i) Potassium Bromide (aq) + Barium iodide (aq) → Potassium iodide (aq) + Barium Bromide(aq)
    (ii) Zinc carbonate (s) → Zinc oxide (s) + carbon dioxide (g)
    (iii) Hydrogen (g) + chlorine (g) → Hydrogen chloride

    Q.The reaction is given by
    Zn + H2 SO4 ZnSO4 + H2
    (i) Write the ionic equation for the reaction
    (ii) The ionic equations can be represented by two half equations.Write these equations.
    (iii) Explain why this is a redox reaction

    Q.What are neutralization reactions? Why are they named so? Give one example?

    What is a Chemical change:-

    • It is the process of formation of new substances with new properties
    • Examples are the fermentation of fruit, cooking of food, digestion of food, burning of fuel, respiration etc.
    Do not add acid in the water
    Chemical reaction and equation class 10 notes and Question answer 9

    What is a Chemical reaction:-

    • It is the chemical change in which new products are formed from old reactants.
    • Those substances that take part in the chemical reaction are called reactant
    • Those substances which are formed in the chemical reaction are called Product

    Also, check Other MCQ QUIZ

    Class-12 Co-ordination compound Test papers pdf

    Class-12 Haloalkane and Haloarene test papers pdf


    Chemical reaction and equation class 10
    Chemical reaction and equation class 10

    What is a chemical equation:-

    • It is the representation of a chemical reaction by using symbols and formulae.
    • Reactants are written in left side while product are written in right side.
      • Reactant and Product are separated by single-headed arrow
      • Some examples are given below-
    • Combustion of Hydrocarbons:
      • CH4 (methane) + 2O2 → CO2 + 2H2O
    • Rusting of Iron:
      • 4 Fe + 3 O2 → 2 Fe2O3
    • Photosynthesis:
      • 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
    • Respiration:
      • C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
    • Fermentation:
      • C6H12O6 → 2 C2H5OH + 2 CO2
    • Acid-Base Neutralization:
      • HCl + NaOH → NaCl + H2O
    • Precipitation Reaction:
      • AgNO3 + NaCl → AgCl + NaNO3
    • Hydrolysis of Salt:
      • Na2CO3 + 2 HCl → 2 NaCl + H2O + CO2
    • Oxidation of Hydrogen Peroxide:
      • 2 H2O2 → 2 H2O + O2
    • Decomposition of Hydrogen Peroxide:
      • 2 H2O2 → 2 H2O + O2
    • Synthesis of Water:
      • 2 H2 + O2 → 2 H2O
    • Electrolysis of Water:
      • 2 H2O → 2 H2 + O2 (using electricity)
    • Precipitation of Silver Iodide:
      • 2 AgNO3 + KI → 2 AgI + 2 KNO3
    • Formation of Ammonium Chloride:
      • NH3 + HCl → NH4Cl
    • Synthesis of Ammonia:
      • N2 + 3 H2 → 2 NH3
    • Esterification:
      • CH3COOH + C2H5OH → CH3COOC2H5 + H2O
    • Polymerization of Ethylene:
      • n C2H4 → (C2H4)n (Polyethylene)
    • Hydrogenation of Vegetable Oils:
      • C18H36O2 + 3 H2 → C18H36O2 + 3 H2
    • Saponification:
      • Triglyceride + 3 NaOH → Glycerol + 3 Soap
    • Ammonium Nitrate Decomposition (Explosive):
      • NH4NO3 → N2 + 2 H2O + 1/2 O2

    Chemical reaction and equation class 10
    Chemical reaction and equation class 10 notes and Question answer 10

    What is a Balanced and Unbalanced Chemical Equation?

    • An equation having an equal number of atoms of different elements on the reactant as well as product side is called a Balanced chemical equation.
    • An equation having an unequal number of atoms of different elements on the reactant as well as product side is called an Unbalanced chemical equation.

    How many types of chemical reactions?

    What is a Combination reaction?

    Chemical reaction and equation class 10
    Chemical reaction and equation class 10 notes and Question answer 11
    • It is the reaction in which two or more reactant combine to form single product
    • CaO + H2O → Ca(OH)2

    What is a Decomposition reaction?

    Chemical reaction and equation class 10
    Chemical reaction and equation class 10 notes and Question answer 12
    • It is the reaction in which single reactant is broken down to form two or more product
    • 2 H2O → 2 H2 + O2 (using electricity)

    What is a Single displacement reaction?

    Chemical reaction and equation class 10
    Chemical reaction and equation class 10 notes and Question answer 13
    • It is the reaction where more reactive element displace less reactive element from the compound
      • Zn + CuSO4 → FeSO4 + Cu

    What is a Double displacement reaction?

    Chemical reaction and equation class 10
    Chemical reaction and equation class 10 notes and Question answer 14

    What is a Redox reaction?

    Redox reactions involve oxidation and reduction. The important concepts relating to redox reactions are:

    I.Classical Concept: According to this concept oxidation is the process of addition of oxygen/electronegative element to a substance or removal of hydrogen/electropositive element from a substance.

    Reduction is the process of removal of oxygen/electronegative element from a substance or addition of hydrogen/electropositive element to a substance.

    Substance which is oxidised is called reducing agent and the substance which is reduced is called oxidising agent.

    If oxidation and reduction take place simultaneously, the process is called Redox reaction.

    i.e. reduction + oxidation → Redox reactions

    E.g. Zn + CuO → ZnO + Cu

    Here Zn is converted to ZnO. i.e oxygen is added to Zn. So it is oxidised and hence the reducing agent. CuO is

    converted to Cu. i.e. oxygen is removed from Cu. So it is reduced and hence it is the oxidising agent.

    Other examples are:

    1. FeCl3 + H2 → FeCl2 + 2HCl

    Here the electronegative Cl atom is removed from FeCl3. So it is reduced. H2 is oxidised since an

    electronegative Cl atom is added to it. FeCl3 is the oxidising agent and H2 is the reducing agent.

    2. 2 H2S(g) + O2 (g) → 2 S (s) + 2 H2O (l)

    Here H2S is oxidised and O2 is reduced.

    II. Electronic Concept: According to this concept oxidation is the process of removal (losing) of electron and reduction is the process of addition (gaining) of electron. A redox reaction is the process of exchange of electrons between two or more substances.

    A substance that accepts electron is called oxidising agent and a substance that donates electron is called a reducing agent.

    E.g. In the reaction Zn + Cu2+ → Zn2+ + Cu, Zn loses two electrons and forms Zn2+. So it is oxidised. Cu2+ gains two electrons and forms Cu. So it is reduced. Here Zn is the reducing agent and Cu2+ is the oxidising agent.

    What is the Exothemic reaction?

    What is the Endothermic reaction?

    Corrosion

    It is the process of formation of oxide or other compounds of metal on its surface by the action of air, water-vapor, CO2 etc.

    Some common examples are The rusting of iron, tarnishing of silver, formation of a green coating on copper and bronze (verdigris) etc.

    The most familiar example of corrosion is the rusting of iron. It occurs in the presence of water and air. It is a redox reaction.

    At a particular spot of the metal, oxidation takes place and that spot behaves as the anode. Here Fe is oxidized to Fe2+.

    2 Fe (s)→2 Fe2+ + 4 e

    Electrons released at anodic spot move through the metal and go to another spot on the metal and reduce oxygen in presence of H+ . This spot behaves as cathode. The reaction taking place at this spot is:

    O2(g) + 4 H+(aq) + 4 e ⎯→ 2 H2O (l )

    The overall reaction is:

    2Fe(s)+O2(g) + 4H+(aq) → 2Fe2 + (aq)+ 2 H2O (l )

    The ferrous ions (Fe2+) are further oxidised to ferric ions (Fe3+) and finally to hydrated ferric oxide (Fe2O3. xH2O), which is called rust.

    Methods to prevent corrosion

    1. By coating the metal surface with paint, varnish etc.

    2. By coating the metal surface with another electropositive metal like zinc, magnesium etc. The

    coating of metal with zinc is called Galvanization and the resulting iron is called galvanized iron.

    3. By coating with anti-rust solution.

    4. An electrochemical method is to provide a sacrificial electrode of another metal (like Mg, Zn, etc.)

    which corrodes itself but saves the object (sacrificial protection)

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