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Redox Reactions

Long Answer Type

61.

Show that oxidation cannot occur without reduction.
Or
Show that oxidation and reduction go side by side.

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62. In the following reactions:

space space left parenthesis straight i right parenthesis space straight H subscript 2 straight O space plus space 2 FeCl subscript 3 space space space space space rightwards arrow space space space space 2 FeCl subscript 2 space plus space 2 HCl space plus space straight S space space left parenthesis ii right parenthesis space 2 Al space plus space Fe subscript 2 straight O subscript 3 space space rightwards arrow space space space Al subscript 2 straight O subscript 3 space plus space 2 Fe

which is oxidised to what and which is reduced to what? Also, mention the oxidising and reducing agent.

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Short Answer Type

63.
Identify the oxidant and the reductant in the following reactions:
$left parenthesis straight i right parenthesis space Zn left parenthesis straight s right parenthesis space plus space 1 half straight O subscript 2 left parenthesis straight g right parenthesis space space rightwards arrow space space ZnO left parenthesis straight s right parenthesis left parenthesis ii right parenthesis space Zn left parenthesis straight s right parenthesis space plus space 2 straight H to the power of plus left parenthesis aq right parenthesis space space rightwards arrow space space Zn to the power of 2 plus end exponent left parenthesis aq right parenthesis space plus space straight H subscript 2 left parenthesis straight g right parenthesis$

In reaction (i) zinc donates electrons to O to give zinc and oxide ions. Therefore, Zn acts as a reductant while oxygen acts as an oxidant.

In reaction (ii) Zn transfers its electrons to H⁺and therefore, zinc acts as a reductant and H⁺ acts as an oxidant.

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64. In the reactions given below, identify the species undergoing oxidation and reduction:

left parenthesis straight i right parenthesis space straight H subscript 2 straight S left parenthesis straight g right parenthesis space plus space Cl subscript 2 left parenthesis straight g right parenthesis space space rightwards arrow space space space 2 HCl space left parenthesis straight g right parenthesis space plus space space straight S left parenthesis straight s right parenthesis left parenthesis ii right parenthesis space 3 Fe subscript 3 straight O subscript 4 left parenthesis straight s right parenthesis space plus space 8 Al space left parenthesis straight s right parenthesis space rightwards arrow space space space 9 space Fe left parenthesis straight s right parenthesis space plus space 4 Al subscript 2 straight O subscript 3 left parenthesis straight s right parenthesis left parenthesis iii right parenthesis space 2 Na left parenthesis straight s right parenthesis space plus space straight H subscript 2 left parenthesis straight g right parenthesis space rightwards arrow space space 2 NaH left parenthesis straight s right parenthesis

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65. Using Stock notation, represent the following compounds : HAuCl₄, Tl₂O,FeO, Fe₂O₃, CuI, CuO, MnO and MnO₂?

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66.

How will you classify the redox reactions?

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Long Answer Type

67.

What are the changes which take place when a redox reaction is carried in a beaker? Explain with the help of a suitable example.
Or
Explain the redox reaction

$Zn space plus space CuSO subscript 4 space space rightwards arrow space space ZnSO subscript 4 space plus space Cu$
occurring in a beaker.

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68.

What do you mean by redox reactions in aqueous solutions? Give examples.

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Short Answer Type

69.

Write the half reactions for each of the following redox reactions:
$left parenthesis straight a right parenthesis space 2 Fe to the power of 3 plus end exponent left parenthesis aq right parenthesis space plus space 2 straight I to the power of minus left parenthesis aq right parenthesis space space rightwards arrow space space straight I subscript 2 left parenthesis straight s right parenthesis space plus space 2 Fe to the power of 2 plus end exponent left parenthesis aq right parenthesis left parenthesis straight b right parenthesis space Sn to the power of 2 plus end exponent left parenthesis aq right parenthesis space plus space 2 Hg to the power of 2 plus end exponent left parenthesis aq right parenthesis space rightwards arrow space space Sn to the power of 4 plus end exponent left parenthesis aq right parenthesis space plus space 2 straight H to the power of plus left parenthesis aq right parenthesis$

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Long Answer Type

70. In the following reactions:

1. space 2 Na left parenthesis straight s right parenthesis space plus space Cl subscript 2 left parenthesis straight g right parenthesis space space space rightwards arrow space space space 2 NaCl left parenthesis straight s right parenthesis 2. space Mg left parenthesis straight s right parenthesis space plus space Cl subscript 2 left parenthesis straight g right parenthesis space space rightwards arrow space space MgCl subscript 2 left parenthesis straight s right parenthesis 3. space Zn left parenthesis straight s right parenthesis space plus space 2 straight H to the power of plus left parenthesis aq right parenthesis space space rightwards arrow space space Zn to the power of 2 plus end exponent left parenthesis aq right parenthesis space plus space straight H subscript 2 left parenthesis straight g right parenthesis

Mention:
(i) Which reactant is oxidised? To what?
(ii) Which reactant is an oxidising agent?
(iii) Which reactant is reduced?
(iv) Which reactant is reducing agent?

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