Question Pool Redox Reaction and Rate of Chemical Reactions

Redox Reaction and Rate of Chemical Reactions - SAMAGRA Question Pool & Answers | Class 9 English Medium

Kerala Syllabus SAMAGRA SCERT SAMAGRA Question Pool for Class 9 English Medium Chemistry Redox Reaction and Rate of Chemical Reactions

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Qn 1.

Catalysts are substances which alter the rate of chemical reactions

How do positive catalysts and negative catalysts differ from each other? Explain by citing examples



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Qn 2.

Equal volumes of sodium thio sulphate solution is taken in two boiling tubes. Heat one boiling tube for sometime. Add dilute hydrochloric acid in equal amounts in both the boiling tubes. Sulphur precipitates faster in the boiling tube which is heated.

a) Write down the chemical equation of the above reaction.

b) Name the factor that affects the rate of reaction in this experiment.

c) Why does the rate of reaction increase here?



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Qn 3.

a) Describe an experiment to prove that rate of reaction increases with increase in temperature.

b) Why does the rate of reaction increase with increase in temperature?



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Qn 4.

Analyse the figure and answer the question given below.

 

IMAGE

In which beaker the rate of reaction is faster? Give reason



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Qn 5.

Consider the reaction

Zn + 2HCl → ZnCl2+ H2

Which of the following methods can be used to increase the rate of reaction?

a)Decrease the temperature

b)Concentration of HCl is increased.

c)Powdered zinc is used.

d)Concentration of HCl is decreased.



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Qn 6.

Choose the oxidation reactions from the following.

a) Zn → Zn+2 +2e-

b) Cu2+ +2e- → Cu

c) Mg → Mg 2++2e-

d) Zn2++ 2e→ Zn



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Qn 7.

Zn 0 + Cu+2SO4 -2 → Zn+ 2SO-2 + Cu0

Does the chemical equation given above represent a redox reaction?

Give reason



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Qn 8.

Examine the given equations and answer the following questions .

Zn0 + 2H+1Cl -1 → Zn+2Cl2 -1 + H20

Are the statements given below correct? Justify your answer.

a) Zn gets oxidised

b) HCl is the oxidising agent.



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Qn 9.

Fe + 2HCl → FeCl2 + H2

a) Find the oxidation state of Fe in FeCl2

b) Identify the oxidising agent and reducing agent in the given equation.



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Qn 10.

2 Na + Cl2 → 2NaCl

Analyse the equation and fill up the table given below

The oxidised atom

----------

Equation of oxidation

Na → Na+ +1e-

Reduced atom

-------------

Equation of reduction

Cl+ 1e - → Cl-

Oxidising agent

------------

Reducing agent

--------------

 

  • Answer)

    The oxidised

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    Qn 11.

    Balance the following chemical equations.

    a) Mg + O2 → MgO

    b) Na + O2  Na2O

    c)Mg(OH)2 + H2SO MgSO4 +H2O

    d) KClO KCl+ O2



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    Qn 12.

    The chemical equation given below represents the reaction between hydrogen and oxygen producing water.

    H+ O→ H2O

    Is the given equation balanced? Give reason.



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    Qn 13.

    From the statements given below ,find the wrong one. Rewrite it correctly.

    a) In a chemical reaction mass is neither created nor destroyed.

    b) The total mass of the products will be greater than the total mass of the reactants.

    c) In a chemical reaction ,the total number of atoms of each element in the reactant side and that in the product side are equal.



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    Qn 14.

    A few chemicals are given .

     

    NaCl, AgNO3, Na2S2O3, BaCl2, HCl

     

    a. Choose the suitable chemicals from the box and plan an experiment to prove that temperature influences the rate of reaction

    b. What is your observation?

    c. Which is the substance formed as a result of the reaction taking place?



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    Qn 15.

    Name the catalyst which reduces the rate of decomposition of hydrogen peroxide?



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    Qn 16.

    Take two test tubes A and B. Take equal volumes of sodium thiosulphate solution in both test tubes. Heat test tube A. Add equal volumes of dilute hydrochloric acid in both test tubes.

    a. In which test tube the reaction is faster?

    b. Which is the factor that affects rate of reaction here?.

    c. Explain why the rate of reaction is faster in this test tube



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    Qn 17.

    14 Take 5ml hydrogen peroxide (H2O2 ) solution in a test tube. Add some MnOinto it..

    a. Which is the gas evolved ?How will you identify it?

    b.What is the function of MnOin this reaction?



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    Qn 18.

    Which one of the following does not affect the rate of reaction?

    (temperature, pressure, colour of reactants, concentration)



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    Qn 19.

    Take 5ml of hydrogen peroxide (H2O2) solution in a test tube. Add some manganese dioxide (MnO2 ) into it.

    a. Which is the gas evolved ?

    b. What is the function of MnOin this reaction?

    c. Which are the substances remaining in the test tube when the reaction is over?‍



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    Qn 20.

    IMAGE

    Analyse the figure given above and answer the following questions.

    a. Identify the gas formed in this reaction?

    b. In which beaker the rate of reaction is faster? Give reason

    c. Suggest any other method to increase the rate of collision?



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    Qn 21.

    Analyse the given reaction and answer the following questions.

    CaCO3 + 2HCl  CaCl2 + H2O + ------X-------

    a. Which is the product X formed here ?

    b. Suggest any two methods to increase the amount of products in the given reaction



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    Qn 22.

    Analyse the figure given below and answer the following questions.

    IMAGE

    a. In which test tube is the rate of reaction faster?

    b. Which is the factor that influences the rate of reaction in this case?

    c. Write down the balanced chemical equation of the reaction taking place here.



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    Qn 23.

    Zn+ Cu2+(SO4)22-  Zn2+(SO4)2 2-+ Cu0

    Analyse the given equation and answer the following questions.

    a. Which element gets oxidised?

    b.Which element /ion gets reduced?

    c. Which is the oxidising agent?

    d. Which is the reducing agent?



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    Qn 24.

    Examine the given reaction

    Fe + 2HCl → FeCl2 + H2

    Does this reaction represent a redox reaction ?Justify your answer



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    Qn 25.

    Choose oxidation reactions from the following and write them.

    i) Zn  Zn2+ + 2e-

    ii) F + 1e - F -

    iii) Cl +1e-  Cl-

    iv) Mg Mg2+ + 2e-



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    Qn 26.

    Unbalanced and incomplete chemical equations are given. Fill up the gaps by selecting from the formulae of the molecules given in brackets.Also balance the given equations.

    a) Zn + 2HCl   --a--  +  H2

    b) 2Mg + --b--   2MgO

    c) 4Al +3O →  -----c-----

    (hint: O2,  ZnCl2,  Al2O3)



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    Qn 27.

    Hydrogen peroxide decomposes to give oxygen.

    A student wrote the chemical equation of this reaction as follows.

    H2O2 H2O + O

    a) Which are the reactants and products in this reaction? .

    b)Are the molecular formulae of reactants and products written here correct ? If not rewrite them correctly.

    c)write the balanced chemical equation for this reaction.



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    Qn 28.

    NaCl + AgNO3 NaNO+ AgCl

    When 58.5g NaCl reacts completely with 170g AgNO3 , 85g NaNO3 is formed.Calculate the mass of AgCl formed in this reaction? Justify your answer.



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    Qn 29.

    .Find the relation and fill up suitably

    Atomic theory : John Dalton

    Law of conservation of mass: ..................



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    Qn 30.

    Mg0 + 2H+1Cl-1 → Mg+2Cl2-1 + H20

    Analyse the given chemical equation and answer the following questions.

    a) Which atom/ ion gets oxidised?

    b) Which atom/ ion gets reduced?

    c) Which is the oxidising agent ?

    d) Identify the reducing agent?



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