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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान इयत्ता ११

Consider the reactions: 2SX2OX3X(2−)(aq)+lX2(S)⟶SX4OX6X(2−)(aq)+2lX−(aq) SX2OX3X(2−)(aq)+2BrX2(l)+5HX2O(l)⟶2SOX4X2−(aq)+4BrX−(aq)+10HX+(aq) Why does the same reductant, thiosulphate react

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प्रश्न

Consider the reactions:

\[\ce{2S_2O_3^{(2-)}(aq) + l_2(S) -> S_4O_6^{(2-)}(aq) + 2l-(aq)}\]

\[\ce{S_2O_3^{(2-)}(aq) + 2Br_2(l) + 5H_2O(l) -> 2SO_4^{2-} (aq) + 4Br-(aq) + 10H+ (aq)}\]

Why does the same reductant, thiosulphate react differently with iodine and bromine?

संख्यात्मक
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उत्तर

The average oxidation number (O.N.) of `"S"_2"O"_3^(2-)` in is +2. Being a stronger oxidising agent than I2, Br2 oxidises `"S"_2"O"_3^(2-)` to `"SO"_4^(2-)`, in which the O.N. of S is +6. However, I2 is a weak oxidising agent. Therefore, it oxidises `"S"_2"O"_3^(2-)` to `"S"_4"O"_6^(2-)`, in which the average O.N. of S is only +2.5. As a result, `"S"_2"O"_3^(2-)` reacts differently with iodine and bromine.

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पाठ 7: Redox Reactions - EXERCISES [पृष्ठ २८१]

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एनसीईआरटी Chemistry - Part 1 and 2 [English] Class 11
पाठ 7 Redox Reactions
EXERCISES | Q 8.14 | पृष्ठ २८१

संबंधित प्रश्‍न

Justify that the following reaction is redox reaction:

\[\ce{4BCl3(g) + 3LiAlH4(s) → 2B2H6(g) + 3LiCl(s) + 3 AlCl3(s)}\]


Justify that the following reaction is redox reaction:

\[\ce{2K(s) + F2(g) → 2K+F– (s)}\]


While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?


Identify the substance oxidised, reduced, oxidising agent and reducing agent for the following reaction:

\[\ce{N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(l)}\]


Why does the following reaction occur?

\[\ce{XeO^{4-}_6 (aq) + 2F- (aq) + 6H+ (aq) -> XeO3(g) + F_2(g) + 3H_2O(l)}\]

What conclusion about the compound Na4XeO6 (of which `"XeO"_6^(4+)` is a part) can be drawn from the reaction.


Consider the reactions:

  1. \[\ce{H3PO2(aq) + 4 AgNO3(aq) + 2 H2O(l) → H3PO4(aq) + 4Ag(s) + 4HNO3(aq)}\]
  2. \[\ce{H3PO2(aq) + 2CuSO4(aq) + 2 H2O(l) → H3PO4(aq) + 2Cu(s) + H2SO4(aq)}\]
  3. \[\ce{C6H5CHO(l) + 2[Ag (NH3)2]+(aq) + 3OH–(aq) → C6H5COO–(aq) + 2Ag(s) + 4NH3 (aq) + 2 H2O(l)}\]
  4. \[\ce{C6H5CHO(l) + 2Cu^{2+}(aq) + 5OH–(aq) → No change observed}\]

What inference do you draw about the behaviour of Ag+ and Cu2+ from these reactions?


Refer to the periodic table given in your book and now answer the following questions:

Select the possible non-metals that can show disproportionation reaction.


Which of the following is not an example of redox reaction?


Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.

Reason (R): The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in \[\ce{O2}\] and –2 oxidation state in \[\ce{H2O}\].


Assertion (A): Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.

Reason (R): In the representation \[\ce{E^Θ_{Fe^{3+}/Fe^{2+}}}\] and \[\ce{E^Θ_{Cu^{2+}/Cu}, Fe^{3+}/Fe^{2+}}\] and \[\ce{Cu^{2+}/Cu}\] are redox couples.


Write redox couples involved in the reactions given.

\[\ce{Br2 + 2Cl- -> Cl2 + 2Br-}\]


Write redox couples involved in the reactions given.

\[\ce{Fe + Cd^{2+} -> Cd + Fe^{2+}}\]


Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.

\[\ce{NaClO4, NaClO3, NaClO, KClO2, Cl2O7, ClO3, Cl2O, NaCl, Cl2 , ClO2}\].

Which oxidation state is not present in any of the above compounds?


Which of the following statement is CORRECT for the decomposition reaction of KClO3

\[\ce{2KClO3 → 2KCl +3O2}\]


Which of the following reactions is the metal displacement reaction? Choose the right option.


The reaction of sulphur in alkaline medium is given below:

\[\ce{S8(s) + {a} OH^-(aq) -> {b} S^{2-}(aq) + {c} S2O^{2-}3(aq) + {d} H2O(l)}\]

The values of 'a' are ______. (Integer answer)


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