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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.
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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:
\[\ce{Cl_{2(s)} + SO_{2(aq)} + 2H_2O_{(l)} -> 2Cl-_{(aq)} + SO^{2-}_{4(aq)} + 4H+_{(aq)}}\]
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.
How do you count for the following observations?
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- \[\ce{MnO-_4 (aq) + SO2 (g) → Mn^{2+} (aq) + HSO-_4 (aq) (in acidic solution)}\]
- \[\ce{H2O2 (aq) + Fe^{2+} (aq) → Fe^{3+} (aq) + H2O (l) (in acidic solution)}\]
- \[\ce{Cr_2O^{2-}_7 + SO2(g) → Cr^{3+} (aq) + SO^{2-}_4 (aq) (in acidic solution)}\]
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\[\ce{N2H4(l) + ClO^-_3 (aq) → NO(g) + Cl–(g)}\]
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\[\ce{Cl_2O_{7(g)} + H_2O_{2(aq)} -> ClO-_{2(aq)} + O_{2(g)} + H+_{(aq)}}\]
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\[\ce{Cr2O^2-_{7(aq)} + SO^2-_{3(aq)}->Cr^3+_{ (aq)} + SO^2-_{4(aq)}(acidic)}\]
Balance the following reaction by oxidation number method.
\[\ce{MnO^-_{4(aq)} + Br^-_{ (aq)}->MnO2_{ (s)} + BrO^-_{3(aq)}(basic)}\]
What is the change in oxidation number of Sulphur in following reaction?
\[\ce{MnO^-_{4(aq)} + SO^{2-}_{3(aq)} -> MnO^{2-}_{4(aq)} + SO^{2-}_{4(aq)}}\]
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\[\ce{Fe^{2+} + H^{+} + Cr2O^{2-}7 -> Cr^{3+} + Fe^{3+} + H2O}\]
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\[\ce{3HCl (aq) + HNO3 (aq) -> Cl2 (g) + NOCl (g) + 2H2O (l)}\]
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\[\ce{Fe2O3 (s) + 3CO (g) ->[Δ] 2Fe (s) + 3CO2 (g)}\]
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