Embed Size (px)
Citation preview
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 series Non 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 acid
Mg + 2HCI → MgCI2 + H2
Zn + H2SO4 → ZnSO4 + H2
Unreactive metal – No rxn with water/acid Au + HCI →
Displacement rxn (REDOX rxn) - reactive metal displace less reactive metal from its sol
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
2K + 2H2O → 2KOH + H2
(0) K oxi – ON ↑ (+1)
(+1) H red – ON ↓ (0)
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(0) Mg oxi – ON ↑ (+2)
(+1) H red – ON ↓ (0)
Reactivity series Non metal, Hydrogen and Carbon
Mg + 2HCI → MgCI2 + H2
Displacement rxn (O atom from less reactive) Reactive metal displace O from less reactive metal 2Al + Fe2O3 → Al2O3 + 2Fe
Zn + PbO → ZnO + Pb
Displacement rxn (O atom from less reactive) Reactive non metal displace O from less reactive metal
3C + 2Fe2O3→ 3CO2 + 4Fe
H2 + CuO→ H2O + Cu
Displacement rxn (less reactive ions) Reactive metal displace less reactive ions from its salt Zn + CuSO4 → ZnSO4 + Cu 2Al + 3CuCI2 → 2AlCI3 + 3Cu
Reactive metals Strong reducing agent
Reducing agent
↓
Oxidation
(0) Ai oxi – ON ↑ (+3)
2Al + 2Fe2O3 → AI2O3 + 2Fe
(+3) Fe red – ON ↓ (0)
Oxidizing agent
↓
Reduction
Zn + CuSO4 → ZnSO4 + Cu
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(0) Zn oxi – ON ↑ (+2)
(+2) Cu red – ON ↓ (0)
Reactivity Series
Reactivity series Metals with water, acids, oxygen
Reactivity series Non 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 acid
Mg + 2HCI → MgCI2 + H2
Zn + H2SO4 → ZnSO4 + H2
Unreactive metal – No rxn with water /acid Au + HCI →
Displacement rxn (REDOX reaction) - reactive metal displace less reactive metal from its sol
Reactivity series Non metal, Hydrogen and Carbon
Displacement rxn (O atom from less reactive) Reactive metal displace O from less reactive metal 2Al + Fe2O3 → Al2O3 + 2Fe
Zn + PbO → ZnO + Pb
Displacement rxn (O atom from less reactive) Reactive non metal displace O from less reactive metal
C + 2Fe2O3→ 3CO2 + 4Fe
H2 + CuO→ H2O + Cu
Displacement rxn (less reactive ions) Reactive metal displace less reactive ions from its salt Zn + CuSO4 → ZnSO4 + Cu 2Al + 3CuCI2 → 2AlCI3 + 3Cu
Reactive metals Strong reducing agent
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
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 series Non metal, Hydrogen and Carbon
Reactive metals Strong reducing agent
reactivity
increase Strong
reducing
agent
Oxidation
rxn favour
str
on
g r
ed
ucin
g a
gen
t
str
on
g r
ed
ucin
g a
gen
t
Reactivity series Non metal, Halogen (Gp 7)
Metal → lose elec (Oxidation)
M → M+ +
Non Metal + gain elec → (Reduction)
F + → F-
str
on
g o
xid
izin
g a
gen
t
reactivity
increase
Strong
oxidizing
agent
Reduction
rxn favour
Mg
AI
Zn
Fe
Pb
Cu
Ag
Strongest reducing agent. Oxidized easily (lose e)
Weakest reducing agent. Least readily oxidized
F
CI
Br
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
Reactive metals Strong reducing agent
K ↔ K+ + e
Na ↔ Na+ + e
Ca ↔ Ca2+ + 2e
Mg ↔ Mg2+ + 2e
Al ↔ Al3+ + 3e
Zn ↔ Zn2+ + 2e
Sn ↔ Sn2+ + 2e
Pb ↔ Pb2+ + 2e
Cu ↔ Cu2+ + 2e
Ag ↔ Ag+ + e
Au ↔ 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
Magnesium
nitrate
Zinc
nitrate
Lead
nitrate
Copper
nitrate
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
Zn + CuSO4 → ZnSO4 + Cu
Click here redox practical filter paper
Oxidation ability – Losing electron - +ve ions
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
Reactive metals Strong reducing 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
Magnesium
nitrate
Zinc
nitrate
Lead
nitrate
Copper
nitrate
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
Zn + Cu(NO3)2 → Zn(NO3)2 + Cu
Most reactive
Least
reactive
Zn more reactive
О
О
Cu less reactive
Add Zn into copper nitrate Displacement rxn – Brown Cu ppt deposited Blue sol fades away (Cu2+ conc decrease)
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(0) Zn oxi – ON ↑ (+2)
(+2) Cu red – ON ↓ (0)
Observation
Zn + CuSO4 → ZnSO4 + Cu
Mg > Zn > Pb > Cu
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
Reactive metals Strong reducing agent
Displacement rxn (REDOX rxn) - Reactive metal displace less reactive metal from its sol
• 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
Click here displacement expt
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(NO3)2 + Ag
Less reactive
О
О
Cu more reactive
Add Cu into silver nitrate Displacement rxn – Grey Ag ppt deposited Blue sol forms (Cu2+ conc increases)
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(0) Cu oxi – ON ↑ (+2)
(+1) Ag red – ON ↓ (0)
Observation
Cu + AgNO3 → Cu(NO3)2 + Ag
Mg > Zn > Pb > Cu > Ag
Mg Zn Pb Cu
Click here Cu/AgNO3 displacement
Metal/ Solution
Mg Zn Fe Cu
Hydrochloric acid (HCI)
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
Reactive metals Strong reducing agent
Displacement rxn (REDOX rxn) - Reactive metal displace less reactive metal from its sol
• 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
Click here displacement expt
Result
Zn → Zn2+ + 2e (oxidized) 2H+ + 2e → H2 (reduced)
Zn displaces H+ from its sol
Zn + 2HCI → ZnCI2 + H2
Less reactive
О
О
Zn more reactive Add Zn into Hydrochloric acid Displacement rxn – Effervescence H2 gas seen
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(0) Zn oxi – ON ↑ (+2)
(+1) H red – ON ↓ (0)
Observation
Zn + HCI → ZnCI2 + H2
Mg > Zn > H > Fe > Cu
Mg Zn Fe Cu
H2 production
Metal above Zn able to displace H from acid – H2 gas О
K
Na
Ca Mg
AI
C Zn
H
Fe Sn
Sn Pb
Cu Ag
О
Metal oside
MgO ZnO Fe2O3 CuO
Carbon
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
Reactive metals Strong reducing agent
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
Click here displacement expt
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 seen Brown iron produced
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(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
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
Reactive metals Strong reducing agent
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 reactive
Add Carbon/Aluminium to iron oxide, Fe2O3
Displacement rxn – Effervescence seen CO gas produced Brown iron produced
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(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 → AI2O3 + 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)
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
2AI + Fe2O3 → AI2O3 + 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 reactive О О
CI more reactive
Add CI2 into NaBr
Displacement rxn – reddish brown solution
Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction
(-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
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 increase
Reaction 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 + HOCI
Br2 + H2O -> HBr + HOBr
I2 + H2O -> HI + HOI
Reaction with AgNO3
Adding AgNO3
AgCI – white ppt AgBr - yellow cream ppt AgI – yellow ppt
Kept in seal, reactive Fluorine – yellow gas Chlorine – greenish gas Bromine – brown liquid Iodine – violet solid
Click here video on chlorine chemistry
Similar chemical property - decrease reactivity Chlorine – dissolve quickly – yellowish HOCI Bromine – dissolve slowly – brown HOBr Iodine – slightly soluble - brown HOI
Displacement Reaction
Reactive halogen displace less reactive halogen from its halide solution
Click here video displacement reaction
Strong oxidizing agent
Add NaBr Add NaCI Add NaI Add NaCI Add NaI Add 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 -> ✗
Chemical Properties Group 17
Group 17 (Halogen)
greenish gas
Displacement Reaction
Reactive halogen displace less reactive halogen from its halide solution
CI2 in hexane
Br2 in hexane I2 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
2Li + CI2 -> 2LiCI
2Na + CI2 -> 2NaCI
2K + CI2 -> 2KCI
Chemical Properties Group 1
Size increase Reaction with water
4Li + O2 -> 2Li2O
4Na + O2 -> 2Na2O
4K + 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 flame Sodium – move fast, hissing sound – yellow flame Potassium – move fast, ignite - lilac flame Turn red litmus blue- produce hydrogen gas Solution of metal hydroxide/alkaline produced
Click here video sodium in water
Similar chemical property but diff reactivity Lithium –burn slowly , red flame Sodium – burn brightly, yellow flame Potassium –burn very brightly, lilac flame
Kept in paraffin oil
Strong reducing agent Reduce 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 → CO2+ 2H2O gain oxygen gain oxygen
Zn + CuO → ZnO + Cu PbO + CO → Pb + CO2
loss 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
Gain oxygen ↑ Loss oxygen ↓
Loss hydrogen ↓ Gain hydrogen ↑
Redox (Oxidation and 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 + CO2 PbO + CO → Pb + CO2
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 oxygen ↑ Loss oxygen ↓
Gain oxidation Number ↑
Loss oxidation Number ↓
Loss hydrogen ↓ Gain hydrogen ↑
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→ 3H2O+ 3Cu + N2
Redox (Oxidation and Reduction)
(+7) (+2) Mn red - ON ↓
(+2) Fe oxi – ON ↑ (+3)
MnO4- + Fe2+ + 8H+ → Mn2+ + Fe3+ 4H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation Oxidizing
Agent Reducing
Agent
MnO4- Fe2+
Reduction Oxidation
Oxidizing Agent
Reducing Agent
CI2 Br-
Reduction Oxidation
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
(0) CI red – ON ↓ (-1)
(-1) Br - oxi – ON ↑ (0)
Oxidizing Agent
Reducing Agent
CuO NH3
Reduction Oxidation
Reducing agent
↓
Oxidation
(-3) NH3 oxi – ON ↑ (0)
Oxidizing agent
↓
Reduction (+2) Cu red – ON ↓ (0)
2HCI + Zn → H2 + ZnCI2
(0) Zn oxi – ON ↑ (+2) Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction (+1) H red – ON ↓ (0)
Oxidizing Agent
Reducing Agent
HCI Zn
Reduction Oxidation
CI2 + 2KBr-→ 2KCI + Br2
3CuO + 2NH3→ 3H2O+ 3Cu +N2
Redox (Oxidation and Reduction)
(+7) (+2) Mn red - ON ↓
(+2) Fe oxi – ON ↑ (+3)
MnO4- + 8H+ + Fe2+ → Mn2+ + Fe3+ 4H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
MnO4- + 5e → Mn2+
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
(0) CI red – ON ↓ (-1)
(-1) Br - oxi – ON ↑ (0)
Reducing agent
↓
Oxidation
(-3) NH3 oxi – ON ↑ (0)
Oxidizing agent
↓
Reduction (+2) Cu red – ON ↓ (0)
2HCI + Zn → H2 + ZnCI2
(0) Zn oxi – ON ↑ (+2) Reducing agent
↓
Oxidation
Oxidizing agent
↓
Reduction (+1) H red – ON ↓ (0)
Reducing Agent Oxidation
Fe 2+ → Fe2+ + e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Reducing Agent Oxidation
2Br - → Br2 + 2e-
Loss electron
Increase ON ↑
Oxidizing Agent Reduction
CI2 + 2e → 2CI- Gain electron
Decrease ON ↓
Reducing Agent Oxidation
(NH3) -N3- → N + 3e- Loss electron
Increase ON ↑
Oxidizing Agent Reduction
(CuO) Cu2+ + 2e → Cu Gain electron
Decrease ON ↓
Reducing Agent Oxidation
Zn → Zn2+ + 2e- Loss electron
Increase ON ↑
Oxidizing Agent Reduction
2H+ + 2e → H2
Gain electron
Decrease ON ↓
Redox (Oxidation and Reduction)
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 Agent Reducing Agent
Oxidation rxn Reduction rxn lose electron
Zn + 2H+ → H2 + Zn2+
Zn → Zn2+ + 2e 2H+ + 2e → H2
(0) ON increase ↑ (+2)
Zn → Zn2+ + 2e
2H+ + 2e → H2 2H+ + Zn → Zn2+ + H2
lose electron gain electron
(+1) ON decrease ↓ (0)
Complete full eqn
Zn + Cu2+ → Zn2+ + Cu Oxidation half eqn
Zn → Zn2+ + 2e lose electron
(0) ON increase ↑ (+2)
Reduction half eqn
Cu2+ + 2e → Cu
(+2) ON decrease ↓ (0)
gain electron
Zn → Zn2+ + 2e
Cu2+ + 2e → Cu Cu2+ + Zn → Zn2+ + Cu
Half equations
Redox (Oxidation and Reduction)
Half equations
Oxidation half eqn Reduction half eqn
Zn → Zn2+ + 2e 2H+ + 2e → H2
(0) ON increase ↑ (+2)
Zn → Zn2+ + 2e
2H+ + 2e → H2 2H+ + Zn → Zn2+ + H2
lose electron gain electron
(+1) ON decrease ↓ (0)
Complete full eqn
Oxidation half eqn
Zn → Zn2+ + 2e lose electron
(0) ON increase ↑ (+2)
Reduction half eqn
Cu2+ + 2e → Cu
(+2) ON decrease ↓ (0)
gain electron
Zn → Zn2+ + 2e
Cu2+ + 2e → Cu Cu2+ + Zn → Zn2+ + Cu
Half equations
Zn + 2HCI → H2 + ZnCI2
Zn + 2H+ + 2CI- → H2 + Zn2+ + 2CI -
Complete ionic/redox eqn
Zn + 2H+ → H2 + Zn2+
spectator ions spectator ions
Zn + 2H+ → H2 + Zn2+
Zn + CuSO4 → ZnSO4 + Cu
Zn + Cu2++ SO42- → Zn2+ + SO4
2- + Cu
Complete full eqn
Complete ionic/redox eqn
spectator ions
Zn + Cu2+ → Zn2+ + Cu
Half equations Half equations Zn + Cu2+ → Zn2+ + Cu
Redox (Oxidation and Reduction)
Half equations
Oxidation half eqn Reduction half eqn
Mg → Mg2+ + 2e Pb2+ + 2e → Pb
(0) ON increase ↑ (+2)
Mg → Mg2+ + 2e
Pb2+ + 2e → Pb Pb2+ + Mg → Mg2+ + Pb
lose electron gain electron
(+2) ON decrease ↓ (0)
Complete full eqn
Oxidation half eqn
2Br- → Br2 + 2e
lose electron
(-1) ON increase ↑ (0)
Reduction half eqn
CI2 + 2e → 2CI-
(0) ON decrease ↓ (-1)
gain electron
2Br- → Br2 + 2e
CI2 + 2e → 2CI-
CI2 + 2Br- → 2CI- + Br2
Half equations
Mg + PbO → Pb + MgO
Mg + Pb2+ + O2- → Pb + Mg2+ + O 2-
Complete ionic/redox eqn
spectator ions spectator ions
Mg + Pb2+ → Pb + Mg2+
2KBr + CI2 → Br2 + 2KCI
2K+ + 2Br- + CI2 → Br2 + 2K+ + 2CI -
Complete full eqn
Complete ionic/redox eqn
spectator ions
2Br- + CI2 → Br2 + 2CI-
Half equations Half equations
Mg + Pb2+ → Pb + Mg2+
2Br- + CI2 → Br2 + 2CI-
lose electron
MnO4- + 8H+ + 5Fe2+ → Mn2+ + 5Fe3+ + 4H2O
Constructing Half and complete redox equation
(+7) (+2) Mn red - ON ↓
(+2) Fe oxi – ON ↑ (+3)
MnO4- + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
MnO4- + 5e → Mn2+
Reducing Agent Oxidation
Fe 2+ → Fe2+ + e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O -add H2O
2. Balance # H add H+
3. Balance # charges -add electrons
4. Balance # electron transfer
MnO4- → Mn2+
MnO4- → Mn2+ + 4H2O
MnO4- + 8H+ → Mn2++ 4H2O
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
Fe2+ → Fe3+
Fe2+ → Fe3+ + e-
5Fe2+ → 5Fe3+ + 5e- MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
x 5 x 1
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
5Fe2+ → 5Fe3+ + 5e- +
MnO4- - In acidic medium
- Strong oxidizing agent MnO4
- + 8H+ + 5Fe2+ → Mn2+ + 5Fe3+ 4H2O
2MnO4- + 5SO2+ 2H2O → 2Mn2+ + 5SO4
2- + 4H+
Constructing Half and complete redox equation
(+7) (+2) Mn red - ON ↓
(+4) SO2 oxi – ON ↑ (+6)
2MnO4- + 5SO2 + 2H2O
→ 2Mn2+ + 5SO42- + 4H+
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
MnO4- + 5e → Mn2+
Reducing Agent Oxidation
SO2 → SO4
2- + 2e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer
MnO4- → Mn2+
MnO4- → Mn2+ + 4H2O
MnO4- + 8H+ → Mn2++ 4H2O
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
SO2 → SO4
2-
2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O
x 5 x 2
2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O
5SO2 + 10H2O → 5SO42- + 20H+ + 10e-
+
2MnO4- + 5SO2 + 2H2O
→ 2Mn2+ + 5SO42- 4H+
SO2 + 2H2O
→ SO42-
SO2 + 2H2O
→ SO42- + 4H+
SO2 + 2H2O
→ SO42- + 4H+ + 2e-
5SO2 + 10H2O
→ 5SO42- + 20H+ + 10e-
2MnO4- + 5H2O2 + 6H+ → 2Mn2+ + 5O2
+ 8H2O
Constructing Half and complete redox equations
(+7) (+2) Mn red - ON ↓
(-1) H2O2 oxi – ON ↑ (0)
2MnO4- + 5H2O2 + 6H+ → 2Mn2+ + 5O2
+ 8H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
MnO4- + 5e → Mn2+
Reducing Agent Oxidation
H2O2 → O2
+ 2e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer
MnO4- → Mn2+
MnO4- → Mn2+ + 4H2O
MnO4- + 8H+ → Mn2++ 4H2O
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O
x 5 x 2
2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O
5H2O2 → 5O2 + 10H+ + 10e-
+
2MnO4- + 5H2O2 + 6H+ → 2Mn2+ + 5O2
+ 8H2O
H2O2 → O2
H2O2 → O2 + 2H+
H2O2 → O2 + 2H+ + 2e-
5H2O2 → 5O2 + 10H+ + 10e-
Cr2O72- + 3NO2
- + 8H+ → 2Cr3+ + 3NO3- + 4H2O
Cr2O72-→ 2Cr3+
Constructing Half and complete redox equations
(+6) (+3) Cr red - ON ↓
(+3) NO2- oxi – ON ↑ (+5)
Cr2O72- + 3NO2
- + 8H+ → 2Cr3+ + 3NO3- + 4H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
Cr2O72- + 6e- → 2Cr3+
Reducing Agent Oxidation
NO2- → NO3
- + 2e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 3 x 1
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
3NO2-+ 3H2O → 3NO3
- + 6H+ + 6e- +
Cr2O72- + 3NO2
- + 8H+ → 2Cr3+ + 3NO3- + 4H2O
Cr2O72- → 2Cr3+ + 7H2O
Cr2O72- + 14H+ → 2Cr3+ + 7H2O
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
NO2- → NO3
-
NO2- + H2O → NO3
-
NO2- + H2O → NO3
- + 2H+
NO2- + H2O → NO3
- + 2H+ + 2e-
3NO2- + 3H2O → 3NO3
- + 6H+ + 6e-
Cr2O72- + 6Fe2+ + 14H+ → 2Cr3+ + 6Fe3+ + 7H2O
Cr2O72-→ 2Cr3+
Constructing Half and complete redox equations
(+6) (+3) Cr red - ON ↓
(+2) Fe2+ oxi – ON ↑ (+3)
Cr2O72- + 6Fe2+ + 14H+ → 2Cr3+ + 6Fe3+ + 7H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
Cr2O72- + 6e- → 2Cr3+
Reducing Agent Oxidation
Fe2+ → Fe3+ + e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 6 x 1
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
6Fe2+ → 6Fe3+ + 6e- +
Cr2O72- → 2Cr3+ + 7H2O
Cr2O72- + 14H+ → 2Cr3+ + 7H2O
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
Cr2O72- + 6Fe2+ + 14H+ → 2Cr3+ + 6Fe3+ 7H2O
Fe2+ → Fe3+
Fe2+ → Fe3+ + e
6Fe2+ → 6Fe3+ + 6e
Constructing Half and complete redox equations
(+5) (-1) CIO3 - red - ON ↓
(-1) I- oxi – ON ↑ (0)
CIO3- + 6I- + 6H+ → 3I2 + CI- + 3H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
CIO3- + 6e- → CI-
Reducing Agent Oxidation
2I- → I2 + 2e-
Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 3 x 1
CIO3- + 6H+ + 6e- → CI- + 3H2O
6I- → 3I2 + 6e-
+
CIO3- + 6I- + 6H+ → 3I2 + CI- + 3H2O
CIO3- → CI-
CIO3- → CI- + 3H2O
CIO3- + 6H+ → CI- + 3H2O
CIO3- + 6H+ + 6e- → CI- + 3H2O
CIO3- + 6H+ + 6e- → CI- + 3H2O
2I- → I2
2I- → I2 + 2e-
6I- → 3I2 + 6e-
CIO3- + 6H++ 6I- → 3I2 + 3H2O
Constructing Half and complete redox equations
(+5) (+2) NO3 - red - ON ↓
(0) Cu oxi – ON ↑ (+2)
2NO3- + 3Cu + 8H+ → 3Cu2+ + 2NO + 4H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
NO3- + 3e- → NO
Reducing Agent Oxidation
Cu → Cu2+ + 2e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 3 x 2
2NO3- + 8H+ + 6e- → 2NO + 4H2O
3Cu → 3Cu2+ + 6e- +
2NO3- + 3Cu + 8H+ → 3Cu2+ + 2NO + 4H2O
NO3- → NO
NO3- → NO + 2H2O
NO3- + 4H+ → NO + 2H2O
NO3- + 4H+ + 3e- → NO + 2H2O
2NO3- + 8H+ + 6e- → 2NO + 4H2O
Cu → Cu2+
Cu → Cu2+ + 2e-
3Cu → 3Cu2+ + 6e-
2NO3- + 8H+ + 3Cu → 3Cu2+ +2NO + 4H2O
HNO3 +3Fe2+ + 3H+ → 3Fe3+ + NO + 2H2O
Constructing Half and complete redox equations
(+5) (+2) HNO3 red - ON ↓
(+2) Fe oxi – ON ↑ (+3)
HNO3 + 3Fe2+ + 3H+ → 3Fe3+ + NO + 2H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
HNO3 + 3e- → NO
Reducing Agent Oxidation
Fe 2+ → Fe3+ + e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 3 x 1
HNO3 + 3H+ + 3e- → NO + 2H2O
3Fe2+ → 3Fe3+ + 3e- +
HNO3 → NO + 2H2O
HNO3+ 3H+ → NO + 2H2O
HNO3 + 3H+ + 3e- → NO + 2H2O
HNO3 + 3H+ + 3e- → NO + 2H2O
Fe2+ → Fe3+
HNO3 + 3Fe2+ + 3H+ → 3Fe3+ + NO + 2H2O
HNO3 → NO
Fe2+ → Fe3+ + e-
3Fe2+ → 3Fe3+ + 3e-
H2O2 + 2Fe2+ +2H+ → 2Fe3+ + 2H2O
Constructing Half and complete redox equations
(-1) (-2) H2O3 red - ON ↓
(+2) Fe oxi – ON ↑ (+3)
H2O2 + 2Fe2+ + 2H+ → 2Fe3+ + 2H2O
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
H2O3 + e- → H2O
Reducing Agent Oxidation
Fe 2+ → Fe3+ + e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer x 2 x 1
H2O2 + 2H+ + 2e- → 2H2O
2Fe2+ → 2Fe3+ + 2e- +
Fe2+ → Fe3+
Fe2+ → Fe3+ + e-
2Fe2+ → 2Fe3+ + 2e-
H2O2 + 2Fe2+ + 2H+ → 2Fe3+ + 2H2O
H2O2 → H2O
H2O2 → 2H2O
H2O2 + 2H+ → 2H2O
H2O2 + 2H+ + 2e- → 2H2O
H2O2 + 2H+ + 2e- → 2H2O
CI2 + SO2 + 2H2O → 2CI- + SO4
2- + 4H+
Constructing Half and complete redox equations
(0) (-1) CI2 red - ON ↓
(+4) SO2 oxi – ON ↑ (+6)
CI2 + SO2 + 2H2O
→ 2CI- + SO42- + 4H+
Oxidizing agent
↓
Reduction
Reducing agent
↓
Oxidation
Oxidizing Agent Reduction
CI2 + 2e → 2CI-
Reducing Agent Oxidation
SO2 → SO4
2- + 2e- Loss electron
Increase ON ↑
Gain electron
Decrease ON ↓
Complete full eqn Oxidation half eqn Reduction half eqn
1. Balance # O - add H2O
2. Balance # H add H+
3. Balance # charges - add electrons
4. Balance # electron transfer
SO2 → SO4
2-
x 1 x 1
CI2 + 2e- → 2CI-
SO2 + 2H2O → SO42- + 4H+ + 2e-
+
SO2 + 2H2O
→ SO42-
SO2 + 2H2O
→ SO42- + 4H+
SO2 + 2H2O
→ SO42- + 4H+ + 2e-
CI2 + SO2 + 2H2O
→ 2CI- + SO42- + 4H+
CI2 → 2CI-
CI2 + 2e- → 2CI-
CI2 + 2e- → 2CI-
SO2 + 2H2O
→ SO42- + 4H+ + 2e-
MnO4- (Acidic medium)
- Strong oxidizing agent
- Gain 5 e-
MnO4- - (Neutral medium)
- Moderate oxidizing agent
- Gain 3 e
MnO4- + 2H2O + 3e- →MnO2 + 4OH-
MnO4- - (Basic medium)
- Weak oxidizing agent
- Gain 1 e
Disproportional Reaction
Substance both oxidized and reduced simultaneously Substance acts as oxidizing and reducing agent
Redox Reaction
(-1) Br - oxi – ON ↑ (0)
(0) CI red – ON ↓ (-1)
CI2 + 2KBr-→ 2KCI + Br2
Reducing agent - oxidized Oxidizing agent – reduced
Oxidizing
Agent
Reducing
Agent
Concept Map
Redox Reaction in diff medium
(-1) H2O2 red – ON ↓ (-2)
H2O2 → H2O + 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 → HNO3 + 2NO + 2H2O
(+3) HNO2 oxi – ON ↑ (+5)
Cu2SO4 → CuSO4
+ Cu
(+1) Cu red – ON ↓ (0)
(+1) Cu oxi – ON ↑ (+2)
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
(+7) ON decrease ↓ (+2)
(+7) ON decrease ↓ (+4)
MnO4- + e- → MnO4
2-
(+7) ON decrease ↓ (+6)
Sn2+ + 2Fe3+ → Sn4+ + 2Fe2+ 2Fe2+ + CI2 → 2Fe3+ + 2CI- Ca + 2H+ → Ca2+ + H2
IB Redox Questions
Deduce half eqn of oxidation and reduction for the following
Ca + 2H+ → Ca2+ + H2 2Fe2+ + CI2
→ 2Fe3+ + 2CI- Sn2+ + 2Fe3+ → Sn4+ + 2Fe2+
0 +1 +2 0
Ca → Ca2+ + 2e
2H+ + 2e → H2
oxidation
reduction
+2 0 +3 -1
2Fe2+ → Fe3+ + 2e
CI2 + 2e → 2CI-
oxidation
reduction
+2 +3 +4 +2
Sn2+ → Sn4+ + 2e
2Fe3+ + 2e → 2Fe2+
Substances acting as oxidizing and reducing agent
2MnO4- + 5H2O2 + 6H+ → 2Mn2+ + 5O2
+ 8H2O
H2O2 + 2Fe2+ + 2H+ → 2Fe3+ + 2H2O
H2O2 + 2I- + 2H+ → I2
+ 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+ → 2Mn2+ + 5As2O5 + 8H2O 2NO3- + 3Cu + 8H+ → 3Cu2+ + 2NO + 4H2O
Cr2O72- + 3NO2
- + 8H+ → 2Cr3+ + 3NO3- + 4H2O
1 2
3
oxidizing
agent
oxidizing
agent
oxidizing
agent
reducing
agent reducing
agent
reducing
agent
