ib chemistry on redox, reactivity series and displacement reaction

http://lawrencekok.blogspot.com

Prepared by Lawrence Kok

Tutorial on Redox, Reactivity Series and Displacement reactions.

http://lawrencekok.blogspot.com/

Reactivity Series

• Metal arranged according to their ability to lose electron - form +ve ions• Measure tendency of metals in losing electrons (Undergo oxidation)• Metals – lose electrons – form electropositive ions – Oxidation Process

Reactivity series Metals with water, acids, oxygen

Reactivity seriesNon metal, Hydrogen and Carbon

Displacement rxn (H atom from H2O/HCI)Reactive metal displace H atom from water 2K + 2H2O → 2KOH + H2

Ca + 2H2O → Ca(OH)2 + H2

Less reactive metal displace H atom from acidMg + 2HCI → MgCI2 + H2

Zn + H2SO4 → ZnSO4 + H2

Unreactive metal – No rxn with water/acidAu + HCI →

Displacement rxn (REDOX rxn)-reactive metal displace less reactive metal from its sol

Reducing agent ↓ Oxidation

Oxidizing agent ↓ Reduction

2K + 2H2O 2KOH + H→ 2

(0) K oxi – ON ↑ (+1)

(+1) H red – ON ↓ (0)



(0) Mg oxi – ON ↑ (+2)

(+1) H red – ON ↓ (0)


Mg + 2HCI MgCI→ 2 + H2

Displacement rxn (O atom from less reactive)Reactive metal displace O from less reactive metal2Al + Fe2O3 → Al2O3 + 2Fe Zn + PbO → ZnO + Pb

Displacement rxn (O atom from less reactive)Reactive non metal displace O from less reactive metal3C + 2Fe2O3→ 3CO2 + 4FeH2 + CuO→ H2O + Cu

Displacement rxn (less reactive ions)Reactive metal displace less reactive ions from its salt Zn + CuSO4 → ZnSO4 + Cu2Al + 3CuCI2 → 2AlCI3 + 3Cu

Reactive metals Strong reducing agent


(0) Ai oxi – ON ↑ (+3)

2Al + 2Fe2O3 AI→ 2O3 + 2Fe

(+3) Fe red – ON ↓ (0)


Zn + CuSO4 ZnSO→ 4 + Cu



(0) Zn oxi – ON ↑ (+2)

(+2) Cu red – ON ↓ (0)

Reactivity Series

Reactivity series Metals with water, acids, oxygen


Displacement rxn (H atom from H2O/HCI)Reactive metal displace H atom from water 2K + 2H2O → 2KOH + H2

Ca + 2H2O → Ca(OH)2 + H2

Less reactive metal displace H atom from acidMg + 2HCI → MgCI2 + H2

Zn + H2SO4 → ZnSO4 + H2

Unreactive metal – No rxn with water /acidAu + HCI →

Displacement rxn (REDOX reaction)-reactive metal displace less reactive metal from its sol


Displacement rxn (O atom from less reactive)Reactive metal displace O from less reactive metal2Al + Fe2O3 → Al2O3 + 2FeZn + PbO → ZnO + Pb

Displacement rxn (O atom from less reactive)Reactive non metal displace O from less reactive metalC + 2Fe2O3→ 3CO2 + 4FeH2 + CuO→ H2O + Cu

Displacement rxn (less reactive ions)Reactive metal displace less reactive ions from its salt Zn + CuSO4 → ZnSO4 + Cu2Al + 3CuCI2 → 2AlCI3 + 3Cu


Click here AI/CuCI3 displacement

Click here to view Flinn Scientific

Click here Iron extraction (Thermite)

• Metal arranged according to their ability to lose electron - form +ve ions• Measure tendency of metals in losing electrons (Undergo oxidation)• Metals – lose electrons – form electropositive ions – Oxidation Process

Click here microscale Fe reduction

https://www.youtube.com/watch?v=w6zsIXB0cKg

https://www.youtube.com/watch?v=BMcM1JgZOps

http://www.youtube.com/watch?v=rdCsbZf1_Ng&feature=related

https://www.youtube.com/watch?v=sk3ZolhPyWM

https://www.youtube.com/watch?v=w6zsIXB0cKg

https://www.youtube.com/watch?v=BMcM1JgZOps

http://www.youtube.com/watch?v=rdCsbZf1_Ng&feature=related

https://www.youtube.com/watch?v=sk3ZolhPyWM

Reactivity Series

• Metals arranged according to their ability to lose electron - form +ve ions• Measure tendency of metals in losing electrons (Undergo oxidation)• Metals – lose electrons – form electropositive ions – Oxidation Process



reactivity increase

Strong reducing

agent

Oxidation rxn favour

stro

ng

red

uc

ing

ag

ent

stro

ng

red

uc

ing

ag

ent

Reactivity seriesNon metal, Halogen (Gp 7)

Metal → lose elec (Oxidation) M → M+ +

Non Metal + gain elec → (Reduction)

F + → F-

stro

ng

oxi

diz

ing

ag

ent

reactivity increase

Strong oxidizing

agent

Reduction rxn favour

MgAIZnFePbCuAg

Strongest reducing agent.Oxidized easily (lose e)

Weakest reducing agent.Least readily oxidized

FCIBr I

Metals

Non Metals Halogens

Strongest oxidizing agent.Reduced easily (gain e)

Weakest oxidizing agent.Least readily reduced

Reactivity Series

• Metals arranged according to their ability to lose electron - form +ve ions• Measure tendency of metals in losing electrons (Undergo oxidation)• Metals – lose electrons – form electropositive ions – Oxidation Process


K ↔ K+ + eNa ↔ Na+ + eCa ↔ Ca2+ + 2e

Mg ↔ Mg2+ + 2e

Al ↔ Al3+ + 3e

Zn ↔ Zn2+ + 2e

Sn ↔ Sn2+ + 2e

Pb ↔ Pb2+ + 2e

Cu ↔ Cu2+ + 2e

Ag ↔ Ag+ + eAu ↔ Au+ + e

Potassium metal, K• Strong Reducing Agent• High Tendency lose e↑

Gold metal Au • Weak Reducing Agent• Low ↓ Tendency to lose e

Potassium ion K+

• Weak Oxidising Agent• Low ↓ Tendency gain e

Gold ion Au+ • Strong Oxidising Agent• High Tendency gain e↑

Strong Reducing Agent

Strong Oxidising Agent

Displacement rxn (REDOX rxn)-Reactive metal displace less reactive metal from its sol

• Add Zn, Mg, Cu, Pb into spotting tile• Make observation if rxn happen• Reactive metal displace less reactive metal from it solution• Arrange metal in order of reactivity

Mg Zn Pb Cu

Magnesiumnitrate

Zincnitrate

Lead nitrate

Coppernitrate

Click here displacement expt

Solution/Metal

Mg Zn Pb Cu

Magnesium nitrate

Zinc nitrate

Lead nitrate

Copper nitrate

Result

Zn → Zn 2+ + 2e (oxidized)Cu2+ + 2e → Cu (reduced)

Zn displaces Cu from its sol


Click here redox practical filter paper

Oxidation ability – Losing electron - +ve ions

http://www.rsc.org/learn-chemistry/wiki/index.php?title=TeacherExpt:Displacement_reactions_between_metals_and_their_salts&oldid=4834

https://www.youtube.com/watch?v=HcbbXv-Q1xg

http://www.nuffieldfoundation.org/practical-chemistry/displacement-reactions-between-metals-and-their-salts

https://www.youtube.com/watch?v=HcbbXv-Q1xg

K Na Ca Mg AI C Zn H Fe Sn Pb

Cu Ag

Reactivity Series

• Metal arranged according to their ability to lose electron - form +ve ions• Measure tendency of metals in losing electrons (Undergo oxidation)• Metal – lose electrons – form electropositive ions – Oxidation Process



• Add Zn, Mg, Cu, Pb into spotting tile• Make observation if rxn happen• Reactive metal displace less reactive metal from it solution• Arrange metal in order of reactivity

Mg Zn Pb Cu

Magnesium nitrate

Zincnitrate

Lead nitrate

Coppernitrate


Solution/Metal

Mg Zn Pb Cu

Magnesium nitrate

Zinc nitrate

Lead nitrate

Copper nitrate

Result

Zn → Zn 2+ + 2e (oxidized)Cu2+ + 2e → Cu (reduced)

Zn displaces Cu from its sol

Zn + Cu(NO3)2 Zn(NO→ 3)2 + Cu

Most reactive

Least reactive

Zn more reactive

О

О

Cu less reactive

Add Zn into copper nitrateDisplacement rxn – Brown Cu ppt depositedBlue sol fades away (Cu2+ conc decrease)



(0) Zn oxi – ON ↑ (+2)

(+2) Cu red – ON ↓ (0)

Observation


Mg > Zn > Pb > Cu




Cu Ag

Reactivity Series




• Add Mg, Zn, Pb, Cu to spotting tile with AgNO3

• Make observation if rxn happen• Reactive metal displace less reactive metal from it solution• Arrange metal in order of reactivity

Silver nitrate


Metal/Solution

Mg Zn Pb Cu

Silver nitrate

Result

Cu → Cu2+ + 2e (oxidized)Ag+ + e → Ag (reduced)

Cu displaces Ag+ from its sol

Cu + AgNO3 Cu(NO→ 3)2 + Ag

Less reactive

ОО

Cu more reactive

Add Cu into silver nitrateDisplacement rxn – Grey Ag ppt depositedBlue sol forms (Cu2+ conc increases)



(0) Cu oxi – ON ↑ (+2)

(+1) Ag red – ON ↓ (0)

Observation

Cu + AgNO3 Cu(NO→ 3)2 + Ag

Mg > Zn > Pb > Cu > Ag

Mg Zn Pb Cu

Click here Cu/AgNO3 displacement


https://www.youtube.com/watch?v=k8UtR7akNec




Metal/Solution

Mg Zn Fe Cu

Hydrochloric acid (HCI)


Cu Ag

Reactivity Series




• Add Mg, Zn, Fe, Cu to spotting tile with HCI• Make observation if rxn happen• Reactive metal displace less reactive metal from it solution• Arrange metal in order of reactivity

HCI


Result

Zn → Zn2+ + 2e (oxidized)2H+ + 2e → H2 (reduced)

Zn displaces H+ from its sol

Zn + 2HCI ZnCI→ 2 + H2

Less reactive

ОО

Zn more reactive Add Zn into Hydrochloric acidDisplacement rxn – Effervescence H2 gas seen



(0) Zn oxi – ON ↑ (+2)

(+1) H red – ON ↓ (0)

Observation

Zn + HCI ZnCI→ 2 + H2

Mg > Zn > H > Fe > Cu

Mg Zn Fe Cu

H2 production

Metal above Zn able to displace H from acid – H2 gasО



K Na Ca Mg AI C Zn H Fe Sn Sn

Pb Cu

AgО

Metal oside MgO ZnO Fe2O3 CuO

Carbon

Reactivity Series



Displacement rxn (REDOX rxn)-Reactive metal displace less reactive metal from its oxide/ores

• Add Metal oxide into crucible with Carbon• Make observation if rxn happen• Reactive metal displace less reactive metal from it ores• Arrange metal in order of reactivity

C


Result

C → C2+ + 2e (oxidized)Fe3+ + 3e → Fe (reduced)

C displace Fe3+ from its oxide

3C + Fe2O3 3CO→ + 2Fe

Less reactive

О

C more reactive

Add Carbon into iron oxide, Fe2O3

Displacement rxn – Effervescence CO gas seenBrown iron produced



(0) C oxi – ON ↑ (+2)

(+3) Fe red – ON ↓ (0)

Observation

Mg > C > Zn > Fe > Cu

MgO ZnO Fe2O3 CuO

Iron extraction

3C + Fe2O3 3CO→ + 2Fe

Metal above Pb able to displace Fe from its oxide

О



Metal oxide C AI

Fe2O3


Cu Ag

Reactivity Series



Displacement rxn (REDOX rxn)-Reactive metal displace less reactive metal from its oxide/ores

• Add carbon and aluminium to crucible with Fe2O3

• Make observation if rxn happen• Reactive metal displace less reactive metal from it ores• Arrange metal in order of reactivity

Result

C → C2+ + 2e (oxidized)Fe3+ + 3e → Fe (reduced)

C displace Fe3+ from its oxide

3C + Fe2O3 3CO→ + 2Fe

Less reactive

О

О

AI/C more reactiveAdd Carbon/Aluminium to iron oxide, Fe2O3

Displacement rxn – Effervescence seen CO gas producedBrown iron produced



(0) C oxi – ON ↑ (+2)

(+3) Fe red – ON ↓ (0)

Observation

AI > C > Fe

Iron extraction

3C + Fe2O3 3CO→ + 2Fe

Metal above Pb able to displace Fe from its oxide

2AI + Fe2O3 AI→ 2O3 + 2Fe

Thermite welding

AI → AI3+ + 3e (oxidized)Fe3+ + 3e → Fe (reduced)

Al displace Fe3+ from its oxide

О

(0) AI oxi – ON ↑ (+3)

(+3) Fe red – ON ↓ (0)



2AI + Fe2O3 AI→ 2O3 + 2Fe

F

CI

Br

I

Reactivity Series

• Non metal arranged according to their ability to gain electron - form -ve ion• Measure tendency of non metal in gaining electron (Undergo reduction)• Non Metal – gain electron – form electronegative ion – Reduction Process

Reactive non metals (Halogens, Gp 7) Strong oxidizing agent

Displacement rxn (REDOX rxn)-Reactive halogen displace less reactive halide from its solution

• Add CI2, Br2, I2 into tubes .• Make observation if rxn happen• Reactive halogen displace less reactive halogen from its solution• Arrange halogen in order of reactivity

Result

2Br- → Br2 + 2e (oxidized)

CI + e → CI- (reduced)CI displace Br- from its solution

CI2 + 2NaBr 2NaCI→ + Br2

Br less reactiveОО

CI more reactive

Add CI2 into NaBrDisplacement rxn – reddish brown solution



(-1) Br oxi – ON ↑ (0)

(0) CI red – ON ↓ (-1)

Observation

F > CI > Br > I

О

Halogen/Halide

CI2 Br2 I2

Sodium chloride

Sodium bromide

Sodium iodide Click here video displacement rxn

CI2 + 2NaBr -> 2NaCI + Br2 ✓

CI2 + 2NaI -> 2NaCI + I2 ✓Br2 + NaCI -> ✗Br2 + 2NaI -> 2NaBr + I2 ✓I2 + NaCI -> ✗I2 + NaBr -> ✗

Reactive halogen displace less reactive halogen from its halide solution

CI2 + 2NaBr 2NaCI→ + Br2

Redox rxn gallium beating heart

Result

https://www.youtube.com/watch?v=QHbaZFSU4_Q


http://www.youtube.com/watch?v=g8Tc-5pUbH8

F2 + 2KCI -> 2KF + CI2

CI2 + 2KBr -> 2KCI + Br2

Br2 + 2KI -> 2KBr + I2

Ag+ + CI- -> AgCI

Ag+ + Br- -> AgBr

Ag+ + I- -> AgI

Chemical Properties Group 17

Size increaseReaction with water

Click here video fluorine chemistry

shell

2.7

2.8.7

2.8.8.7

2.8.18.18.7

CI

F

Br

I

Ability attract electron decrease/EN lower

Reactivity decrease

Group 17 (Halogen)

Chemical reaction

CI2 + H2O -> HCI + HOCIBr2 + H2O -> HBr + HOBrI2 + H2O -> HI + HOI

Reaction with AgNO3

Adding AgNO3

AgCI – white pptAgBr - yellow cream pptAgI – yellow ppt

Kept in seal, reactiveFluorine – yellow gasChlorine – greenish gasBromine – brown liquidIodine – violet solid

Click here video on chlorine chemistry

Similar chemical property - decrease reactivityChlorine – dissolve quickly – yellowish HOCI Bromine – dissolve slowly – brown HOBrIodine – slightly soluble - brown HOI

Displacement Reaction


Click here video displacement reaction

Strong oxidizing agent

https://www.youtube.com/watch?v=vtWp45Eewtw

https://www.youtube.com/watch?v=BXCfBl4rmh0

https://www.youtube.com/watch?v=cbFCWFksYoM

http://www.periodicvideos.com/

https://www.youtube.com/watch?v=BXCfBl4rmh0





Add NaBrAdd NaCIAdd NaIAdd NaCIAdd NaIAdd NaBr

violet solid

brown liquid

yellow gas

Click here video displacement rxn

Click here video displacement rxn

CI2 + 2NaBr -> 2NaCI + Br2 ✓

CI2 + 2NaI -> 2NaCI + I2 ✓Br2 + NaCI -> ✗Br2 + 2NaI -> 2NaBr + I2 ✓I2 + NaCI -> ✗I2 + NaBr -> ✗


Group 17 (Halogen)

greenish gas

Displacement Reaction


CI2 in hexane Br2 in hexaneI2 in hexane

Br2 in hexane

I2 in hexane

I2 in hexane

CI2 + 2NaBr -> 2NaCI + Br2 CI2 + 2NaI -> 2NaCI + I2✗ Br2 + 2NaI -> 2NaBr + I2

✗ ✗

Strong oxidizing agent






http://www.periodicvideos.com/














2Li + CI2 -> 2LiCI2Na + CI2 -> 2NaCI2K + CI2 -> 2KCI


Size increaseReaction with water

4Li + O2 -> 2Li2O4Na + O2 -> 2Na2O4K + O2 -> 2K2O

Click here video potassium in water

shell

2.1

2.8.1

2.8.8.1

2.8.8.18.1

Na

Li

K

Rb

lose electron easily electropositive

Reactivity increase

Group 1 (Alkali Metal)

Chemical reaction

2Li + 2H2O -> 2LiOH + H2

2Na + 2H2O -> 2NaOH + H2

2K + 2H2O -> 2KOH + H2

Reaction with oxygen Reaction with halogen

Lithium – move slowly surface water – red flameSodium – move fast, hissing sound – yellow flamePotassium – move fast, ignite - lilac flameTurn red litmus blue- produce hydrogen gas Solution of metal hydroxide/alkaline produced

Click here video sodium in water

Similar chemical property but diff reactivityLithium –burn slowly , red flameSodium – burn brightly, yellow flamePotassium –burn very brightly, lilac flame

Kept in paraffin oil

Strong reducing agentReduce H+ ion to H2 gas(losing e to H+)

Strong reducing agent

Oxidizing agent using potassium chlorate

Redox (Oxidation and Reduction)

Oxidation – Gain of oxygen ↑

Oxidation – Loss of hydrogen ↓ Reduction – Gain of hydrogen ↑

Reduction – Loss of oxygen ↓

Oxidation Reduction

Gain oxygen ↑ Loss oxygen ↓

Gain oxidation Number ↑

Loss oxidation Number ↓

Loss hydrogen ↓ Gain hydrogen ↑

Loss electron ↓ Gain electron ↑

Ca + O2 CaO→ CH4 + 2O2 CO→ 2+ 2H2Ogain oxygen gain oxygen

Zn + CuO ZnO + Cu→ PbO + CO Pb + CO→ 2loss oxygen loss oxygen

H2S + CI2 S +2HCI →loss hydrogen

H2S + CI2 S + 2HCI →

Redox - Oxidation state change- Electron transfer

CH4 + 2O2 → CO2 + 2H2O

gain hydrogen

Zn + CuSO4 → ZnSO4 + Cu Zn + CI2 → ZnCI2

No gain/loss oxygen/hydrogen

Redox

gain oxygen

gain hydrogen

Reduction

Oxidation

Are these redox rxns?

Most rxn does not involve H2

and O2

carbon oxidized

Oxidation Reduction




Rxn involve gain/loss of oxygen/hydrogen

CH4 + 2O2 → CO2 + 2H2O

Gain hydrogen

oxygen reduced

gain oxygen

carbon oxidized

Rxn involve gain/loss of electron

Oxidation Reduction

Gain ON ↑ Loss ON ↓

Loss electron ↓ Gain electron ↑- broader definition- cover more rxn types

lead reduced

gain oxygen

carbon oxidized

(-4) (+4)

(0) (-2)

ON ↑

ON ↓oxygen reduced

carbon oxidized

(+2) (0)lead reduced

(+2) (+4)

CH4 + 2O2 → CO2 + 2H2O

ON ↑

ON ↓loss oxygen

PbO + CO Pb + CO→ 2PbO + CO Pb + CO→ 2

Oxidizing Agent Reducing Agent

Causes Oxidation Cause Reduction

Undergo reduction Undergo oxidation

Gain electron ↑ Loss electron ↓

Decrease oxidation number ↓

Increase oxidation number ↑

Oxidation Reduction


Gain oxidation Number ↑

Loss oxidation Number ↓


Loss electron ↓ Gain electron ↑Oxidizing Agent Reducing Agent

MnO4- Fe2+

Cr2O72- SO2

HNO3 I-

H2O2 H2S

CI2 SO3 2-

CI2 + 2KBr- 2KCI→ + Br2

3CuO + 2NH3 3H→ 2O+ 3Cu + N2


(+7) (+2)Mn red - ON ↓

(+2) Fe oxi – ON ↑ (+3)

MnO4- + Fe2+ + 8H+ Mn→ 2+ + Fe3+ 4H2O



Oxidizing Agent

Reducing Agent

MnO4- Fe2+

Reduction Oxidation

Oxidizing Agent

Reducing Agent

CI2 Br-

Reduction Oxidation



(0) CI red – ON ↓ (-1)

(-1) Br - oxi – ON ↑ (0)

Oxidizing Agent

Reducing Agent

CuO NH3

Reduction Oxidation


(-3) NH3 oxi – ON ↑ (0)

Oxidizing agent ↓ Reduction (+2) Cu red – ON ↓ (0)

2HCI + Zn H→ 2 + ZnCI2

(0) Zn oxi – ON ↑ (+2)Reducing agent ↓ Oxidation


(+1) H red – ON ↓ (0)

Oxidizing Agent

Reducing Agent

HCI Zn

Reduction Oxidation


3CuO + 2NH3 3H→ 2O+ 3Cu +N2


(+7) (+2)Mn red - ON ↓

(+2) Fe oxi – ON ↑ (+3)

MnO4- + 8H+ + Fe2+ Mn→ 2+ + Fe3+ 4H2O



Oxidizing Agent Reduction

MnO4- + 5e Mn→ 2+



(0) CI red – ON ↓ (-1)

(-1) Br - oxi – ON ↑ (0)


(-3) NH3 oxi – ON ↑ (0)

Oxidizing agent ↓ Reduction (+2) Cu red – ON ↓ (0)

2HCI + Zn H→ 2 + ZnCI2

(0) Zn oxi – ON ↑ (+2)Reducing agent ↓ Oxidation


(+1) H red – ON ↓ (0)

Reducing Agent Oxidation

Fe 2+ Fe→ 2+ + e- Loss electronIncrease ON ↑

Gain electronDecrease ON ↓


2Br - Br→ 2 + 2e-

Loss electronIncrease ON ↑


CI2 + 2e 2CI→ - Gain electron

Decrease ON ↓


(NH3) -N3- N→ + 3e- Loss electronIncrease ON ↑


(CuO) Cu2+ + 2e Cu→Gain electronDecrease ON ↓


Zn Zn→ 2+ + 2e- Loss electronIncrease ON ↑


2H+ + 2e H→ 2



Half equations

Oxidation rxn

Oxidation half eqn Reduction half eqn

Loss electron ↓

Reduction rxn

Loss hydrogen ↓ Gain oxygen ↑ Gain ON ↑ Gain electron ↑ Gain hydrogen ↑ Loss oxygen ↓ Loss ON ↓

Oxidizing AgentReducing Agent

Oxidation rxn Reduction rxnlose electron

Zn + 2H+ H→ 2 + Zn2+

Zn Zn→ 2+ + 2e 2H+ + 2e H→ 2

(0) ON increase ↑ (+2)

Zn Zn→ 2+ + 2e2H+ + 2e H→ 2 2H+ + Zn Zn→ 2+ + H2

lose electron gain electron

(+1) ON decrease ↓ (0)

Complete full eqn

Zn + Cu2+ Zn→ 2+ + CuOxidation half eqn

Zn Zn→ 2+ + 2elose electron


Reduction half eqn

Cu2+ + 2e Cu→


gain electron

Zn Zn→ 2+ + 2eCu2+ + 2e Cu→Cu2+ + Zn Zn→ 2+ + Cu

Half equations


Half equations


Zn Zn→ 2+ + 2e 2H+ + 2e H→ 2


Zn Zn→ 2+ + 2e2H+ + 2e H→ 2 2H+ + Zn Zn→ 2+ + H2



Complete full eqn

Oxidation half eqn

Zn Zn→ 2+ + 2elose electron


Reduction half eqn

Cu2+ + 2e Cu→


gain electron Zn Zn→ 2+ + 2eCu2+ + 2e Cu→Cu2+ + Zn Zn→ 2+ + Cu

Half equations

Zn + 2HCI H→ 2 + ZnCI2

Zn + 2H+ + 2CI- H→ 2 + Zn2+ + 2CI -

Complete ionic/redox eqn

Zn + 2H+ H→ 2 + Zn2+

spectator ionsspectator ions

Zn + 2H+ H→ 2 + Zn2+


Zn + Cu2++ SO42- Zn→ 2+ + SO4

2- + Cu

Complete full eqn


spectator ions

Zn + Cu2+ Zn→ 2+ + Cu

Half equations Half equationsZn + Cu2+ Zn→ 2+ + Cu


Half equations


Mg Mg→ 2+ + 2e Pb2+ + 2e Pb→(0) ON increase ↑ (+2)

Mg Mg→ 2+ + 2ePb2+ + 2e Pb →Pb2+ + Mg Mg→ 2+ + Pb



Complete full eqn

Oxidation half eqn

2Br- Br→ 2 + 2e

lose electron

(-1) ON increase ↑ (0)

Reduction half eqn

CI2 + 2e 2CI→ -

(0) ON decrease ↓ (-1)

gain electron 2Br- Br→ 2

+ 2eCI2

+ 2e 2CI→ -

CI2 + 2Br- 2CI→ - + Br2

Half equations

Mg + PbO Pb→ + MgO

Mg + Pb2+ + O2- Pb → + Mg2+ + O 2-


spectator ionsspectator ions

Mg + Pb2+ Pb→ + Mg2+

2KBr + CI2 Br→ 2 + 2KCI

2K+ + 2Br- + CI2 Br→ 2 + 2K+ + 2CI -

Complete full eqn


spectator ions

2Br- + CI2 Br→ 2 + 2CI-

Half equations Half equations

Mg + Pb2+ Pb→ + Mg2+

2Br- + CI2 Br→ 2 + 2CI-

lose electron

MnO4- + 8H+ + 5Fe2+ Mn→ 2+ + 5Fe3+ + 4H2O

Constructing Half and complete redox equation

(+7) (+2)Mn red - ON ↓

(+2) Fe oxi – ON ↑ (+3)

MnO4- + 5Fe2+ + 8H+ Mn→ 2+ + 5Fe3+ + 4H2O




MnO4- + 5e Mn→ 2+




Complete full eqnOxidation half eqnReduction half eqn

1. Balance # O -add H2O

2. Balance # H add H+

3. Balance # charges -add electrons

4. Balance # electron transfer

MnO4- Mn→ 2+

MnO4- Mn→ 2+ + 4H2O

MnO4- + 8H+ Mn→ 2++ 4H2O

MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

Fe2+ Fe→ 3+

Fe2+ Fe→ 3+ + e-

5Fe2+ 5Fe→ 3+ + 5e-MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

x 5x 1

MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

5Fe2+ 5Fe→ 3+ + 5e-+

MnO4- - In acidic medium

- Strong oxidizing agentMnO4

- + 8H+ + 5Fe2+ Mn→ 2+ + 5Fe3+ 4H2O

2MnO4- + 5SO2+ 2H2O 2Mn→ 2+ + 5SO4

2- + 4H+

Constructing Half and complete redox equation

(+7) (+2)Mn red - ON ↓

(+4) SO2 oxi – ON ↑ (+6)

2MnO4- + 5SO2 + 2H2O 2Mn→ 2+ + 5SO4

2- + 4H+




MnO4- + 5e Mn→ 2+


SO2 SO→ 4

2- + 2e- Loss electronIncrease ON ↑



1. Balance # O - add H2O


3. Balance # charges - add electrons


MnO4- Mn→ 2+

MnO4- Mn→ 2+ + 4H2O

MnO4- + 8H+ Mn→ 2++ 4H2O

MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

SO2 SO→ 4

2-

2MnO4- + 16H+ + 10e- 2Mn→ 2+ + 8H2O

x 5x 2

2MnO4- + 16H+ + 10e- 2Mn→ 2+ + 8H2O

5SO2 + 10H2O 5SO→ 42- + 20H+ + 10e-+

2MnO4- + 5SO2 + 2H2O 2Mn→ 2+ + 5SO4

2- 4H+

SO2 + 2H2O SO→ 4

2-

SO2 + 2H2O SO→ 4

2- + 4H+

SO2 + 2H2O SO→ 4

2- + 4H+ + 2e-

5SO2 + 10H2O 5SO→ 4

2- + 20H+ + 10e-

2MnO4- + 5H2O2 + 6H+ 2Mn→ 2+ + 5O2

+ 8H2O

Constructing Half and complete redox equations

(+7) (+2)Mn red - ON ↓

(-1) H2O2 oxi – ON ↑ (0)

2MnO4- + 5H2O2 + 6H+ 2Mn→ 2+ + 5O2

+ 8H2OOxidizing agent ↓ Reduction



MnO4- + 5e Mn→ 2+


H2O2 O→ 2

+ 2e- Loss electronIncrease ON ↑


Complete full eqn Oxidation half eqnReduction half eqn





MnO4- Mn→ 2+

MnO4- Mn→ 2+ + 4H2O

MnO4- + 8H+ Mn→ 2++ 4H2O

MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

2MnO4- + 16H+ + 10e- 2Mn→ 2+ + 8H2O

x 5x 2

2MnO4- + 16H+ + 10e- 2Mn→ 2+ + 8H2O

5H2O2 5O→ 2 + 10H+ + 10e-+

2MnO4- + 5H2O2 + 6H+ 2Mn→ 2+ + 5O2

+ 8H2O

H2O2 O→ 2

H2O2 O→ 2 + 2H+

H2O2 O→ 2 + 2H+ + 2e-

5H2O2 5O→ 2 + 10H+ + 10e-

Cr2O72- + 3NO2

- + 8H+ 2Cr→ 3+ + 3NO3- + 4H2O

Cr2O72- 2Cr→ 3+


(+6) (+3)Cr red - ON ↓

(+3) NO2- oxi – ON ↑ (+5)

Cr2O72- + 3NO2

- + 8H+ 2Cr→ 3+ + 3NO3- + 4H2O




Cr2O72- + 6e- 2Cr→ 3+


NO2- NO→ 3

- + 2e- Loss electronIncrease ON ↑






4. Balance # electron transferx 3x 1

Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

3NO2-+ 3H2O 3NO→ 3

- + 6H+ + 6e-+

Cr2O72- + 3NO2

- + 8H+ 2Cr→ 3+ + 3NO3- + 4H2O

Cr2O72- 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

NO2- NO→ 3

-

NO2- + H2O NO→ 3

-

NO2- + H2O NO→ 3

- + 2H+

NO2- + H2O NO→ 3

- + 2H+ + 2e-

3NO2- + 3H2O 3NO→ 3

- + 6H+ + 6e-

Cr2O72- + 6Fe2+ + 14H+ 2Cr→ 3+ + 6Fe3+ + 7H2O

Cr2O72- 2Cr→ 3+


(+6) (+3)Cr red - ON ↓

(+2) Fe2+ oxi – ON ↑ (+3)

Cr2O72- + 6Fe2+ + 14H+ 2Cr→ 3+ + 6Fe3+ + 7H2O




Cr2O72- + 6e- 2Cr→ 3+


Fe2+ Fe→ 3+ + e- Loss electronIncrease ON ↑







Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

6Fe2+ 6Fe→ 3+ + 6e-+

Cr2O72- 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

Cr2O72- + 14H+ + 6e- 2Cr→ 3+ + 7H2O

Cr2O72- + 6Fe2+ + 14H+ 2Cr→ 3+ + 6Fe3+ 7H2O

Fe2+ Fe→ 3+

Fe2+ Fe→ 3+ + e

6Fe2+ 6Fe→ 3+ + 6e


(+5) (-1)CIO3 - red - ON ↓

(-1) I- oxi – ON ↑ (0)

CIO3- + 6I- + 6H+ 3I→ 2 + CI- + 3H2O




CIO3- + 6e- CI→ -


2I- I→ 2 + 2e- Loss electron

Increase ON ↑







CIO3- + 6H+ + 6e- CI→ - + 3H2O

6I- 3I→ 2 + 6e-+

CIO3- + 6I- + 6H+ 3I→ 2 + CI- + 3H2O

CIO3- CI→ -

CIO3- CI→ - + 3H2O

CIO3- + 6H+ CI→ - + 3H2O

CIO3- + 6H+ + 6e- CI→ - + 3H2O

CIO3- + 6H+ + 6e- CI→ - + 3H2O

2I- I→ 2

2I- I→ 2 + 2e-

6I- 3I→ 2 + 6e-

CIO3- + 6H++ 6I- 3I→ 2 + 3H2O


(+5) (+2) NO3 - red - ON ↓

(0) Cu oxi – ON ↑ (+2)

2NO3- + 3Cu + 8H+ 3Cu→ 2+ + 2NO + 4H2O




NO3- + 3e- NO→


Cu Cu→ 2+ + 2e- Loss electronIncrease ON ↑







2NO3- + 8H+ + 6e- 2NO→ + 4H2O

3Cu 3Cu→ 2+ + 6e-+

2NO3- + 3Cu + 8H+ 3Cu→ 2+ + 2NO + 4H2O

NO3- NO→

NO3- NO + 2H→ 2O

NO3- + 4H+ NO + 2H→ 2O

NO3- + 4H+ + 3e- NO + 2H→ 2O

2NO3- + 8H+ + 6e- 2NO + 4H→ 2O

Cu Cu→ 2+

Cu Cu→ 2+ + 2e-

3Cu 3Cu→ 2+ + 6e-

2NO3- + 8H+ + 3Cu 3Cu→ 2+ +2NO + 4H2O

HNO3 +3Fe2+ + 3H+ 3Fe→ 3+ + NO + 2H2O


(+5) (+2) HNO3 red - ON ↓

(+2) Fe oxi – ON ↑ (+3)

HNO3 + 3Fe2+ + 3H+ 3Fe→ 3+ + NO + 2H2O




HNO3 + 3e- NO→









HNO3 + 3H+ + 3e- NO→ + 2H2O 3Fe2+ 3Fe→ 3+ + 3e-+

HNO3 NO + 2H→ 2O

HNO3+ 3H+ NO + 2H→ 2O

HNO3 + 3H+ + 3e- NO + 2H→ 2O

HNO3 + 3H+ + 3e- NO + 2H→ 2O

Fe2+ Fe→ 3+

HNO3 + 3Fe2+ + 3H+ 3Fe→ 3+ + NO + 2H2O

HNO3 NO→

Fe2+ Fe→ 3+ + e-

3Fe2+ 3Fe→ 3+ + 3e-

H2O2 + 2Fe2+ +2H+ 2Fe→ 3+ + 2H2O


(-1) (-2) H2O3 red - ON ↓

(+2) Fe oxi – ON ↑ (+3)

H2O2 + 2Fe2+ + 2H+ 2Fe→ 3+ + 2H2O




H2O3 + e- H→ 2O









H2O2 + 2H+ + 2e- 2H→ 2O 2Fe2+ 2Fe→ 3+ + 2e-+

Fe2+ Fe→ 3+

Fe2+ Fe→ 3+ + e-

2Fe2+ 2Fe→ 3+ + 2e-

H2O2 + 2Fe2+ + 2H+ 2Fe→ 3+ + 2H2O

H2O2 H→ 2O

H2O2 2H→ 2O

H2O2 + 2H+ 2H→ 2O

H2O2 + 2H+ + 2e- 2H→ 2O

H2O2 + 2H+ + 2e- 2H→ 2O

CI2 + SO2 + 2H2O 2CI→ - + SO4

2- + 4H+


(0) (-1)CI2 red - ON ↓

(+4) SO2 oxi – ON ↑ (+6)

CI2 + SO2 + 2H2O 2CI→ - + SO4

2- + 4H+




CI2 + 2e 2CI→ -


SO2 SO→ 4

2- + 2e- Loss electronIncrease ON ↑







SO2 SO→ 4

2-

x 1x 1

CI2 + 2e- 2CI→ -

SO2 + 2H2O SO→ 42- + 4H+ + 2e-+

SO2 + 2H2O SO→ 4

2-

SO2 + 2H2O SO→ 4

2- + 4H+

SO2 + 2H2O SO→ 4

2- + 4H+ + 2e-

CI2 + SO2 + 2H2O 2CI→ - + SO4

2- + 4H+

CI2 2CI→ -

CI2 + 2e- 2CI→ -

CI2 + 2e- 2CI→ - SO2

+ 2H2O SO→ 42- + 4H+ + 2e-

MnO4- (Acidic medium)

- Strong oxidizing agent- Gain 5 e-

MnO4- - (Neutral medium)

- Moderate oxidizing agent- Gain 3 e

MnO4- + 2H2O + 3e- MnO→ 2 + 4OH-

MnO4- - (Basic medium)

- Weak oxidizing agent- Gain 1 e

Disproportional Reaction

Substance both oxidized and reduced simultaneouslySubstance acts as oxidizing and reducing agent

Redox Reaction

(-1) Br - oxi – ON ↑ (0)

(0) CI red – ON ↓ (-1)


Reducing agent - oxidizedOxidizing agent – reduced

Oxidizing Agent

Reducing Agent

Concept Map

Redox Reaction in diff medium

(-1) H2O2 red – ON ↓ (-2)

H2O2 H→ 2O + 1/2O2

(-1) H2O2 oxi – ON ↑ (0)

(0) CI2 red – ON ↓ (-1)

CI2 + H2O HOCI→ + HCI

(0) CI2 oxi – ON ↑ (+1)

(+3) HNO2 red – ON ↓ (+2)

HNO2 HNO→ 3 + 2NO + 2H2O

(+3) HNO2 oxi – ON ↑ (+5)

Cu2SO4 CuSO→ 4

+ Cu

(+1) Cu red – ON ↓ (0)

(+1) Cu oxi – ON ↑ (+2)

MnO4- + 8H+ + 5e- Mn→ 2+ + 4H2O

(+7) ON decrease ↓ (+2)


MnO4- + e- MnO→ 4

2-


Sn2+ + 2Fe3+ Sn→ 4+ + 2Fe2+2Fe2+ + CI2 2Fe→ 3+ + 2CI-Ca + 2H+ Ca→ 2+ + H2

IB Redox Questions

Deduce half eqn of oxidation and reduction for the following

Ca + 2H+ Ca→ 2+ + H22Fe2+ + CI2

2Fe→ 3+ + 2CI- Sn2+ + 2Fe3+ Sn→ 4+ + 2Fe2+

0 +1 +2 0

Ca Ca→ 2+ + 2e

2H+ + 2e H→ 2

oxidation

reduction

+2 0 +3 -1

2Fe2+ Fe→ 3+ + 2e

CI2 + 2e 2CI→ -

oxidation

reduction

+2 +3 +4 +2

Sn2+ Sn→ 4+ + 2e

2Fe3+ + 2e 2Fe→ 2+

Substances acting as oxidizing and reducing agent

2MnO4- + 5H2O2 + 6H+ 2Mn→ 2+ + 5O2

+ 8H2O

H2O2 + 2Fe2+ + 2H+ 2Fe→ 3+ + 2H2O

H2O2 + 2I- + 2H+ I→ 2 + 2H2O

Oxidizing Agent Reducing Agent

MnO4- Fe2+

Cr2O72- SO2

HNO3 I-

H2O2 H2S

CI2 SO3 2-

Acidified H2O2 act as oxidizing agent- Oxidizes Fe2+ to Fe3+

- Oxidizes I- to I2

Acidified MnO4- act as more powerful oxidizing agent

-Oxidizes weaker oxidizing agent H2O2 to H2O and O2

- H2O2 act as reducing agent

Identify oxidizing and reducing agent for following rxn.

5As2O3 + 2MnO4

- + 16H+ 2Mn→ 2+ + 5As2O5 + 8H2O 2NO3- + 3Cu + 8H+ 3Cu→ 2+ + 2NO + 4H2O

Cr2O72- + 3NO2

- + 8H+ 2Cr→ 3+ + 3NO3- + 4H2O

1 2

3

oxidizing agent

oxidizing agent

oxidizing agent

reducing agent

reducing agent

reducing agent

Acknowledgements

Thanks to source of pictures and video used in this presentation

Thanks to Creative Commons for excellent contribution on licenseshttp://creativecommons.org/licenses/

Prepared by Lawrence Kok

Check out more video tutorials from my site and hope you enjoy this tutorialhttp://lawrencekok.blogspot.com

ib chemistry on redox, reactivity series and displacement reaction

Education

reactivereactive metal

h2ohcireactive metal

reactive ionsreactive

solreactivity seriesnon

carbondisplacement rxn

carbondisplacement rxn

oxidation metals

iron extraction thermite