Advertisements
Advertisements
Question
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.
Solution
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:
\[\ce{Cl_{2(s)} + SO_{2(aq)} + 2H_2O_{(l)} -> 2Cl-_{(aq)} + SO^{2-}_{4(aq)} + 4H+_{(aq)}}\]
APPEARS IN
RELATED QUESTIONS
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?
Balance the following reaction by oxidation number method.
\[\ce{Cr2O^2-_{7(aq)} + SO^2-_{3(aq)}->Cr^3+_{ (aq)} + SO^2-_{4(aq)}(acidic)}\]
Balance the following reaction by oxidation number method.
\[\ce{MnO^-_{4(aq)} + Br^-_{ (aq)}->MnO2_{ (s)} + BrO^-_{3(aq)}(basic)}\]
Balance the following reaction by oxidation number method.
\[\ce{Bi(OH)_{3(s)} + Sn(OH)^-_{3(aq)}->Bi_{(s)} + Sn(OH)^2-_{6(aq)}(basic)}\]
Identify coefficients 'x' and 'y' for the following reaction.
\[\ce{{x}H2O2_{(aq)} + ClO^-_{4(aq)} -> 2O2_{(g)} + ClO^-_{2(aq)} + {y}H2O_{(l)}}\]
What is the change in oxidation number of Sulphur in following reaction?
\[\ce{MnO^-_{4(aq)} + SO^{2-}_{3(aq)} -> MnO^{2-}_{4(aq)} + SO^{2-}_{4(aq)}}\]
Identify the oxidising agent in the following reaction:
\[\ce{CH4_{(g)} + 2O2_{(g)} -> CO2_{(g)} + 2H2O_{(l)}}\]
When methane is burnt completely, oxidation state of carbon changes from ______.
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.
\[\ce{I2 + NO^{-}3 -> NO2 + IO^{-}3}\]
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.
\[\ce{PCl3 (l) + 3H2O (l) -> 3HCl (aq) + H3PO3 (aq)}\]
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.
\[\ce{Cr2O^{2-}7 + Fe^{2+} + H+ -> Cr^{3+} + Fe^{3+} + H2O}\]
Balance the following ionic equations.
\[\ce{MnO^{-}4 + H^{+} + Br^{-} -> Mn^{2+} + Br2 + H2O}\]
In \[\ce{Cu^{2+} + Ag -> Cu + Ag^+}\], oxidation half-reaction is:
