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Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of - Chemistry

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प्रश्न

Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations.

दीर्घउत्तर

उत्तर

Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. This can be illustrated as follows:

(i) P4 and F2 are reducing and oxidising agents respectively.

If an excess of P4 is treated with F2, then PF3 will be produced, wherein the oxidation number (O.N.) of P is +3.

\[\ce{P4 (excess) + F2 -> ^{+3}PF3}\]

However, if P4 is treated with an excess of F2, then PF5 will be produced, wherein the O.N. of P is +5.

\[\ce{P4 + F2 (excess) -> ^{+5}PF5}\]

(ii) K acts as a reducing agent, whereas O2 is an oxidising agent.

If an excess of K reacts with O2, then K2O will be formed, wherein the O.N. of O is –2.

\[\ce{4K (excess) + O2 -> 2K2 ^{-2}O}\]

However, if K reacts with an excess of O2, then K2O2 will be formed, wherein the O.N. of O is –1.

\[\ce{2K + O2 (excess) -> K2 ^{-1}O2}\]

(iii) C is a reducing agent, while O2 acts as an oxidising agent.

If an excess of C is burnt in the presence of insufficient amount of O2, then CO will be produced, wherein the O.N. of C is +2.

\[\ce{C (excess) + O2 -> ^{+2}CO}\]

On the other hand, if C is burnt in an excess of O2, then CO2 will be produced, wherein the O.N. of C is +4.

\[\ce{C + O2 (excess) -> ^{+4}CO2}\]

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Balancing Redox Reactions in Terms of Loss and Gain of Electrons
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पाठ 8: Redox Reactions - EXERCISES [पृष्ठ २८१]

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एनसीईआरटी Chemistry - Part 1 and 2 [English] Class 11
पाठ 8 Redox Reactions
EXERCISES | Q 8.11 | पृष्ठ २८१

संबंधित प्रश्‍न

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\[\ce{O3(g) + H2O2(l) → H2O(l) + 2O2(g)}\]

Why it is more appropriate to write these reaction as:

\[\ce{O3(g) + H2O2 (l) → H2O(l) + O2(g) + O2(g)}\]

Also, suggest a technique to investigate the path of the redox reactions.


How do you count for the following observations?

Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why? Write a balanced redox equation for the reaction.


Balance the following redox reactions by ion-electron method:

  1. \[\ce{MnO-_4 (aq) + I– (aq) → MnO2 (s) + I2(s) (in basic medium)}\]
  2. \[\ce{MnO-_4 (aq) + SO2 (g) → Mn^{2+} (aq) + HSO-_4  (aq) (in acidic solution)}\]
  3. \[\ce{H2O2 (aq) + Fe^{2+} (aq) → Fe^{3+} (aq) + H2O (l) (in acidic solution)}\]
  4. \[\ce{Cr_2O^{2-}_7 + SO2(g) → Cr^{3+} (aq) + SO^{2-}_4 (aq) (in acidic solution)}\]

Choose the correct option.

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\[\ce{Sn^{2⊕} + 2Fe^{3⊕}->Sn^{4⊕} + 2Fe^{2⊕}}\]


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\[\ce{MnO^-_{4(aq)} + Br^-_{ (aq)}->MnO2_{ (s)} + BrO^-_{3(aq)}(basic)}\]


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\[\ce{Bi(OH)_{3(s)} + Sn(OH)^-_{3(aq)}->Bi_{(s)}  + Sn(OH)^2-_{6(aq)}(basic)}\]


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\[\ce{Bi(OH)_{3(s)} + SnO^2-_{2(aq)}->SnO^2-_{3(aq)} + Bi^_{(s)}(basic)}\]


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\[\ce{2Zn_{(s)} + O2_{(g)} -> 2ZnO_{(s)}}\]


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\[\ce{I2 + NO^{-}3 -> NO2 + IO^{-}3}\]


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\[\ce{3HCl (aq) + HNO3 (aq) -> Cl2 (g) + NOCl (g) + 2H2O (l)}\]


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\[\ce{HgCl2 (aq) + 2KI (aq) -> HgI2 (s) + 2KCl (aq)}\]


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\[\ce{4NH3 (g) + 3O2 (g) -> 2N2 (g) + 6H2O (g)}\]


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\[\ce{Cr2O^{2-}7 + Fe^{2+} + H+ -> Cr^{3+} + Fe^{3+} + H2O}\]


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\[\ce{Re2O7 + CO -> Re2(CO)10 + CO2}\]

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Consider the following reaction:

\[\ce{xMnO^-_4 + yC2O^{2-}_4 + zH^+ -> xMn^{2+} + 2{y}CO2 + z/2H2O}\]

The values of x, y, and z in the reaction are, respectively:


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