Advertisements
Advertisements
Question
Balance the following redox equation by half-reaction method.
\[\ce{H2C2O_{4(aq)} + MnO^-_{4(aq)}->CO2_{(g)} + Mn^2+_{( aq)}(acidic)}\]
Advertisements
Solution
\[\ce{H2C2O_{4(aq)} + MnO^-_{4(aq)}->CO2_{(g)} + Mn^2+_{( aq)}}\]
Step 1: Write the unbalanced equation for the redox reaction. Assign the oxidation number to all the atoms in reactants and products. Divide the equation into two half equations.
- Oxidation half-reaction: \[\ce{H2C2O_{4(aq)}->CO2_{(g)}}\]
- Reduction half-reaction: \[\ce{MnO^-_{4(aq)}->Mn^2+_{( aq)}}\]
Step 2: Balance the atoms except O and H in each half equation. Balance half equation for O atoms by adding 4H2O to the right side of the reduction half equation.
- Oxidation: \[\ce{H2C2O_{4(aq)}->2CO2_{(g)}}\]
- Reduction: \[\ce{MnO^-_{4(aq)}->Mn^2+_{( aq)} + 4H2O_{(l)}}\]
Step 3: Balance H atoms by adding H+ ions to the side with less H. Hence, add 2H+ ions to the right side of the oxidation half equation and 8H+ ions to the left side of the reduction half equation.
- Oxidation: \[\ce{H2C2O_{4(aq)}->2CO2_{(g)} + 2H^+_{( aq)}}\]
- Reduction: \[\ce{MnO^-_{4(aq)} + 8H^+_{( aq)}->Mn^2+_{( aq)} + 4H2O_{(l)}}\]
Step 4: Now add 2 electrons to the right side of the oxidation half equation and 5 electrons to the left side of the reduction half equation to balance the charges.
- Oxidation: \[\ce{H2C2O_{4(aq)}->2CO2_{(g)} + 2H^+_{( aq)} + 2e^-}\]
- Reduction: \[\ce{MnO^-_{4(aq)} + 8H^+_{( aq)} + 5e^-->Mn^2+_{( aq)} + 4H2O_{(l)}}\]
Step 5: Multiply oxidation half equation by 5 and reduction half equation by 2 to equalize the number of electrons in two half equations. Then add two half equations.
- Oxidation: \[\ce{5H2C2O_{4(aq)}->10CO2_{(g)} + 10H^+_{( aq)} + 10e^-}\]
- Reduction: \[\ce{2MnO^-_{4(aq)} + 16H^+_{( aq)} + 10e^-->2Mn^2+_{( aq)} + 8H2O_{(l)}}\]
Add two half equations:
\[\ce{5H2C2O_{4(aq)} + 2MnO^-_{4(aq)} + 6H^+_{( aq)}->10CO2 + 2Mn^2+_{( aq)} + 8H2O_{(l)}}\]
The equation is balanced in terms of the number of atoms and the charges.
Hence, balanced equation: \[\ce{5H2C2O_{4(aq)} + 2MnO^-_{4(aq)} + 6H^+_{( aq)}->10CO2 + 2Mn^2+_{( aq)} + 8H2O_{(l)}}\]
APPEARS IN
RELATED QUESTIONS
The compound AgF2 is an unstable compound. However, if formed, the compound acts as a very strong oxidizing agent. Why?
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.
Balance the following redox reactions by ion-electron method:
- \[\ce{MnO-_4 (aq) + I– (aq) → MnO2 (s) + I2(s) (in basic medium)}\]
- \[\ce{MnO-_4 (aq) + SO2 (g) → Mn^{2+} (aq) + HSO-_4 (aq) (in acidic solution)}\]
- \[\ce{H2O2 (aq) + Fe^{2+} (aq) → Fe^{3+} (aq) + H2O (l) (in acidic solution)}\]
- \[\ce{Cr_2O^{2-}_7 + SO2(g) → Cr^{3+} (aq) + SO^{2-}_4 (aq) (in acidic solution)}\]
Balance the following equation in the basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.
\[\ce{N2H4(l) + ClO^-_3 (aq) → NO(g) + Cl–(g)}\]
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.
Choose the correct option.
For the following redox reactions, find the correct statement.
\[\ce{Sn^{2⊕} + 2Fe^{3⊕}->Sn^{4⊕} + 2Fe^{2⊕}}\]
Balance the following reaction by oxidation number method.
\[\ce{MnO^-_{4(aq)} + Br^-_{ (aq)}->MnO2_{ (s)} + BrO^-_{3(aq)}(basic)}\]
Balance the following redox equation by half-reaction method.
\[\ce{Bi(OH)_{3(s)} + SnO^2-_{2(aq)}->SnO^2-_{3(aq)} + Bi^_{(s)}(basic)}\]
Which of the following is INCORRECT for the following reaction?
\[\ce{2Zn_{(s)} + O2_{(g)} -> 2ZnO_{(s)}}\]
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?
\[\ce{MnO^-_{4(aq)} + SO^{2-}_{3(aq)} -> MnO^{2-}_{4(aq)} + SO^{2-}_{4(aq)}}\]
When methane is burnt completely, oxidation state of carbon changes from ______.
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.
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.
\[\ce{I2 + NO^{-}3 -> NO2 + IO^{-}3}\]
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.
\[\ce{Fe2O3 (s) + 3CO (g) ->[Δ] 2Fe (s) + 3CO2 (g)}\]
Balance the following ionic equations.
\[\ce{Cr2O^{2-}7 + H^{+} + I- -> Cr^{3+} + I2 + H2O}\]
Balance the following ionic equations.
\[\ce{MnO^{-}4 + SO^{2-}3 + H^{+} -> Mn^{2+} + SO^{2-}4 + H2O}\]
In \[\ce{Cu^{2+} + Ag -> Cu + Ag^+}\], oxidation half-reaction is:
\[\ce{H2O2 -> 2H^+ + O2 + 2e^-}\]; E0 = −0.68 V.
This equation represents which of the following behaviour of H2O2?
