Download App

Redox Reactions — Chemistry STD 11 Science — Question

Maharashtra BoardEnglish MediumSTD 11 ScienceChemistryRedox Reactions6 Marks
Question
Balance the following unbalanced equation (in acidic medium) by ion electron method (half reaction method).
$
Mn _{( aq )}^{2+}+ ClO _{3( qq )}^{-} \longrightarrow MnO _{2( s )}+ ClO _{2( aq )}
$
✓

Answer

Step 1: Write imbalanced equation for the redox reaction. Assign oxidation number to all the atoms in reactants and products. Divide the equation into two half equations.

https://pg-data.sgp1.digitaloceanspaces.com/chapter_wise/15982/y30.png" alt="Image" width="300" height="">
Step 2: Balance the atoms except $O$ and $H$ in each half equation. Balance half equations for $O$ atoms by adding $H _2 O$ to the side with less $O$ atoms. $Add 2 H _2 O$ to left side of oxidation half equation and $1 H _2 O$ to the right side of reduction half equation.
Oxidation: $Mn _{(\text {aq) }}^{2+}+2 H _2 O _{(l)} \longrightarrow MnO _{2(s)}$
Reduction: $ClO _{3(\text { (aq) }}^{-} \longrightarrow ClO _{2(\text {(aq) }}+ H _2 O _{(f)}$

Step 3: Balance $H$ atoms by adding $H +$ ions to the side with less $H$. Hence add $4 H ^{+}$ ions to the right side of oxidation half equation and $2 H ^{+}$ions to the left side of reduction half equation.
Oxidation: $Mn _{(\text {(aq) }}^{2+}+2 H _2 O _{(l)} \longrightarrow MnO _2+4 H _{( aq )}^{+}$
Reduction: $ClO _{3( aq )}^{-}+2 H _{( aq )}^{+} \longrightarrow ClO _{2 \text { (aq) }}+ H _2 O _{(l)}$
Step 4: Now add 2 electrons to the right side of oxidation half equation and 1 electron to the left side of reduction half equation to balance the charges.
Oxidation: $Mn _{(\text {(aq) }}^{2+}+2 H _2 O _{(l)} \longrightarrow MnO _{2(s)}+4 H _{( aq )}^{+}+2 e ^{-}$
Reduction: $ClO _{3(\text { (aq) })}^{-}+2 H _{(\text {aq) }}^{+}+ e ^{-} \longrightarrow ClO _{2( aq )}+ H _2 O _{(l)}$
Step 5: Multiply reduction half equation by 2 to equalize number of electrons in two half equations. Then add two half equation.
Oxidation: $Mn _{( aq )}^{2+}+2 H _2 O _{(l)} \longrightarrow MnO _2+4 H _{( aq )}^{+}+2 e ^{-}$
Reduction: $2 ClO _{3(\text { (aq) }}^{-}+4 H _{(\text {aq) }}^{+}+2 e ^{-} \longrightarrow 2 ClO _{2(\text { (aq) }}+2 H _2 O _{(l)}$
Add two half equations:
$Mn _{( aq )}^{2+}+2 ClO _{3( aq )}^{-} \longrightarrow MnO _{2( s )}+2 ClO _{2( aq )}$
The equation is balanced in terms of number of atoms and the charges.
Hence, balanced equation: $Mn _{( aq )}^{2+}+2 ClO _{3( aq )}^{-} \longrightarrow MnO _{2( s )}+2 ClO _{2( aq )}$+

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Answer the following questions in detail." from Redox Reactions→Redox Reactions — all question types→Chemistry STD 11 Science question papers→Maharashtra Board STD 11 Science question papers→Maharashtra Board question paper generator→

Similar questions

Explain how equilibrium constant helps in predicting the direction of the reaction.
→
Urea $[(NH_2)_2CO]$ is prepared by reacting ammonia with carbon dioxide.
$2NH_{3(g)} + CO_{2(g)} \rightarrow (NH_2)_2CO_{(aq)} + H_2O_{(l)}$
In one process, $637.2 g \ of \ NH_3$ are treated with $1142 g \ of \ CO_2.$
$i.$ Which of the two reactants is the limiting reagent?
$ii.$ Calculate the mass of $(NH_2)_2CO$ formed.
$iii.$ How much excess reagent (in grams) is left at the end of the reaction?
→
The unit of $KC$ is different for different reactions. Explain this statement with suitable examples.
→
Describe the shape of $2p$ orbitals.
→
Explain liquid$-$vapour equilibrium with an example.
→
Balance the following redox equation by oxidation number method. The reactions occur in acidic medium.
$i. \  H _2 O _{2( aq )}+ Cr _2 O _{7( aq )}^{2-} \longrightarrow O _{2( g )}+ Cr _{( mq )}^{3+}$
$ii. \  A g (s)+ N O _{3(\text { (mq) }}^{-} \longrightarrow A g _{(\text {(qq) }}^{+}+ N O _{2( g )}$
$iii. \  Sn _{(\text {(qq) }}^{2+}+ IO _{\text {(teq) }}^{-} \longrightarrow Sn _{( aq )}^{4+}+ I _{(\text {(aq) })}^{-}$
$iv. \  MnO _{4(\text { (q) })}^{-}+ IO _{3(\text { ave }}^{-} \longrightarrow MnO _{2( s )}+ IO _{4( mq )}^{-}$
$v. \  N O _{3( qq )}^{-}+ SO _{2( qq )} \longrightarrow SO _{4( sq )}^{2-}+ NO _{2( g )}$
→
Differentiate between chemical reactions and nuclear reactions.
→
Using oxidation number concept, identify the redox reactions, identify oxidizing and reducing agents in case of redox reactions.
Image
→
Give the different graphical representations of Boyle’s law.
→
Explain the formation of water $(H_2O)$ molecule on the basis of hybridization.
→