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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

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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
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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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अध्याय 7: Redox Reactions - EXERCISES [पृष्ठ २८१]

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एनसीईआरटी Chemistry Part 1 and 2 [English] Class 11
अध्याय 7 Redox Reactions
EXERCISES | Q 8.11 | पृष्ठ २८१

संबंधित प्रश्न

Consider the reaction:

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

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.


Balance the following equation in basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.

\[\ce{Cl_2O_{7(g)} + H_2O_{2(aq)} -> ClO-_{2(aq)} + O_{2(g)} + H+_{(aq)}}\]


Balance the following reaction by oxidation number method.

\[\ce{Cr2O^2-_{7(aq)} + SO^2-_{3(aq)}->Cr^3+_{ (aq)} + SO^2-_{4(aq)}(acidic)}\]


Which of the following is a redox reaction?


What is the change in oxidation number of Sulphur in following reaction?

\[\ce{MnO^-_{4(aq)} + SO^{2-}_{3(aq)} -> MnO^{2-}_{4(aq)} + SO^{2-}_{4(aq)}}\]


Write balanced chemical equation for the following reactions:

Permanganate ion \[\ce{(MnO^{-}4)}\] reacts with sulphur dioxide gas in acidic medium to produce \[\ce{Mn^{2+}}\] and hydrogen sulphate ion.


Write balanced chemical equation for the following reactions:

Reaction of liquid hydrazine \[\ce{(N2H4)}\] with chlorate ion \[\ce{(ClO^{-}3)}\] in basic medium produces nitric oxide gas and chloride ion in gaseous state.


Balance the following equations by the oxidation number method.

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


Balance the following equations by the oxidation number method.

\[\ce{I2 + S2O^{2-}3 -> I- + S4O^{2-}6}\]


Balance the following equations by the oxidation number method.

\[\ce{MnO2 + C2O^{2-}4 -> Mn^{2+} + CO2}\]


Identify the redox reactions out of the following reactions and identify the oxidising and reducing agents in them.

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


Identify the redox reactions out of the following reactions and identify the oxidising and reducing agents in them.

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


Balance the following ionic equations.

\[\ce{Cr2O^{2-}7 + H^{+} + I- -> Cr^{3+} + I2 + H2O}\]


Balance the following ionic equations.

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


In acidic medium, reaction, \[\ce{MNO^-_4 → Mn^2+}\] an example of ____________.   


The weight of CO is required to form Re2(CO)10 will be ______ g, from 2.50 g of Re2O7 according to given reaction

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

Atomic weight of Re = 186.2; C = 12 and O = 16.


On balancing the given redox reaction,

\[\ce{aCr2O7^2- + Bso3^2- (aq) + CH+ (aq) -> 2aCr^3+ (aq) + bSO4^2- (aq) + c(H2O(1)/2}\]

the coefficients a, b and c are found to be, respectively:


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