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Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. - Chemistry

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प्रश्न

Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.

दीर्घउत्तर

उत्तर

The given redox reaction can be represented as:

\[\ce{Cl_{2(s)} + SO_{2(aq)} + H_2O_{(l)} -> Cl-_{(aq)} + SO^{2-}_{4(aq)}}\]

The oxidation half reaction is:

\[\ce{^{+4}SO_{2(aq)} -> ^{+6}SO^{2-}_{4(aq)}}\]

The oxidation number is balanced by adding two electrons as:

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

The charge is balanced by adding 4H+ ions as:

\[\ce{SO_{2(aq)} -> SO^{2-}_{4(aq)} + 4H+_{(aq)} + 2e-}\]

The O atoms and H+ ions are balanced by adding 2H2O molecules as:

\[\ce{SO_{2(aq)} + 2H_2O_{(l)} -> SO^{2-}_{4(aq)} + 4H+_{(aq)} + 2e-}\]   ....(i)

The reduction half reaction is:

\[\ce{Cl_{2(s)} -> Cl-_{(aq)}}\]

The chlorine atoms are balanced as:

\[\ce{^0Cl_{2(s)} -> ^{-1}Cl-_{(aq)}}\]

The oxidation number is balanced by adding electrons

\[\ce{Cl_{2(s)} + 2e- -> 2Cl-_{(aq)}}\]  ....(ii)

The balanced chemical equation can be obtained by adding equation (i) and (ii) as:

\[\ce{Cl_{2(s)} + SO_{2(aq)} + 2H_2O_{(l)} ->  2Cl-_{(aq)} + SO^{2-}_{4(aq)} + 4H+_{(aq)}}\]

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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 २८२]

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एनसीईआरटी Chemistry - Part 1 and 2 [English] Class 11
पाठ 8 Redox Reactions
EXERCISES | Q 8.23 | पृष्ठ २८२

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 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. \[\ce{Cr_2O^{2-}_7 + SO2(g) → Cr^{3+} (aq) + SO^{2-}_4 (aq) (in acidic solution)}\]

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

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


The Mn3+ ion is unstable in solution and undergoes disproportionation to give Mn2+, MnO2, and H+ ion. Write a balanced ionic equation for the reaction.


In Ostwald’s process for the manufacture of nitric acid, the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with 10.00 g. of ammonia and 20.00 g of oxygen?


Justify that the following reaction is redox reaction; identify the species oxidized/reduced, which acts as an oxidant and which acts as a reductant.

\[\ce{2Cu2O_{(S)} + Cu2S_{(S)}->6Cu_{(S)} + SO2_{(g)}}\]


Balance the following reaction by oxidation number method.

\[\ce{H2SO4_{(aq)} + C_{(s)}->CO2_{(g)}  + SO2_{(g)} + H2O_{(l)}(acidic)}\]


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:

Dichlorine heptaoxide \[\ce{(Cl2O7)}\] in gaseous state combines with an aqueous solution of hydrogen peroxide in acidic medium to give chlorite ion \[\ce{(ClO^{-}2)}\] and oxygen gas. (Balance by ion-electron method)


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.

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


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.

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


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

\[\ce{Fe2O3 (s) + 3CO (g) ->[Δ] 2Fe (s) + 3CO2 (g)}\]


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

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


Balance the following ionic equations.

\[\ce{MnO^{-}4 + SO^{2-}3 + H^{+} -> Mn^{2+} + SO^{2-}4 + H2O}\]


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


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