ib chemistry on arrhenius, bronsted lowry conjugate acid base pair and lewis acid
TRANSCRIPT
Brønsted-Lowry Acid - substance that donate proton/proton donorBronsted-Lowry Base – substance that accept proton/proton acceptorOne species donate proton – one species accept proton
Arrhenius acid - substance dissociate in water produce H+ ion.Arrhenius base – substance dissociate in water produce OH- ion.All Arrhenius acid are Bronsted Lowry acid and water must be present
HCI → H+ + CI-
HCI + H2O ↔ H3O+ + CI-
NaOH→ Na+ + OH-
NH3 + H2O ↔ NH4+ + OH-
CO32- + H2O ↔ HCO3
- + OH-
Water/aqueous medium
Water/aqueous mediumOther solvent medium possible
Definition of Acid and Bases
Arrhenius acid Arrhenius base H+ OH-
2
1
gain H+
Acid + Base ↔ Conjugate Base + Conjugate Acid
lose H+
HCI (acid) - CI- (conjugate base)
lose H+
H2O (base) - H3O+ (conjugate acid)
HCI + H2O ↔ CI- + H3O+
gain H+
Lewis Acid - substance that accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance that donate electron/electron donor, lone pair electronLewis Base - donate electron pair forming dative/coordinate bond with Lewis acid
3
HCI + H2O → CI- + H3O+
H2O donate e-HCI accept e-
Lewis acid Lewis base
Conjugate acid base pair differ by one proton
Bronsted Base Bronsted Base
Bronsted Base Bronsted Base
Brønsted-Lowry Acid - substance that donate proton/proton donorBronsted-Lowry Base – substance that accept proton/proton acceptorOne species donate proton – one species accept proton
Arrhenius acid - substance dissociate in water to produce H+ ions.Arrhenius base – substance dissociate in water to produce OH- ions.All Arrhenius acid are Bronsted Lowry acid and water must be present
HCI → H+ + CI-
HCI + H2O ↔ H3O+ + CI-
NaOH→ Na+ + OH-
NH3 + H2O ↔ NH4+ + OH-
CO32- + H2O ↔ HCO3
- + OH-
Water/aqueous medium
Water/aqueous mediumOther solvent medium possible
Acid and Bases
Arrhenius acid Arrhenius base H+ OH-
2
1
Bronsted Base
HPO42- + SO3
2- ↔ PO43- + HSO3
- HCOOH + CN- ↔ HCOO- + HCN
HCI + H2O ↔ H3O+ + CI-
NH4+ + CO2
2- ↔ NH3 + HCO3- CH3COOH + H2O ↔ H3O+ + CH3COO-
Brønsted Acid Brønsted Acid
Brønsted Acid Brønsted Acid
Brønsted Acid Brønsted Acid
Brønsted Acid
Brønsted Acid
Bronsted Base
HF + H2O ↔ F- + H3O+
Bronsted Base
H2PO4- + OH- ↔ HPO4
2- + H2O
Bronsted Base
H2SO4 + N2H5+ ↔ HSO4
- + N2H62+
Brønsted Acid
Bronsted Base
HCO3- + H2O ↔ CO3
2- + H3O+
Brønsted-Lowry Acid - proton donor - Bronsted-Lowry Base – proton acceptorEvery acid has a conjugate base - Every base has a conjugate acidAcid donate proton – Base accept protonConjugate acid has one more H than base - Conjugate base has one fewer H than acid.
Bronsted Lowry Conjugate acid base pair
HCI + H2O ↔ CI- + H3O+
H2O (base) - H3O+ (conjugate acid)
HCI (acid) - CI- (conjugate base)
CH3COOH + H2O ↔ CH3COO- + H3O+
H2O (base) - H3O+ (conjugate acid)
CH3COOH (acid) - CH3COO- (conjugate base)
HF + H2O ↔ F- + H3O+
H2O (base) - H3O+ (conjugate acid)
HF (acid) - F- (conjugate base)
H2SO4 + N2H5+ ↔ HSO4
- +N2H62+
H2SO4 (acid) - HSO4- (conjugate base)
N2H5+ (base) - N2H6
2+(conjugate acid)
HCOOH (acid) - HCOO- (conjugate base)
HCOOH + CN- ↔ HCOO- + HCN
CN- (base) – HCN (conjugate acid)
HPO42- + SO3
2- ↔ PO43- + HSO3
-
HPO42- (acid) - PO4
3- (conjugate base)
SO32- (base) - HSO3
- (conjugate acid)
CONJUGATE
ACID
BASE
gain H+
lose H+
gain H+
lose H+
gain H+
lose H+
gain H+
lose H+
gain H+
lose H+
gain H+
lose H+
gain H+
lose H+
Acid + Base ↔ Conjugate Base + Conjugate Acid
Bronsted Lowry Conjugate acid base pair
HCOOH (acid) - HCOO- (conjugate base)
HCOOH + CN- ↔ HCOO- + HCN HPO42- + SO3
2- ↔ PO43- + HSO3
-
HPO42- (acid) - PO4
3- (conjugate base)
SO32- (base) - HSO3
- (conjugate acid)
NH3 + H2O ↔ NH4+ + OH-
H2O (acid) - OH- (conjugate base)
NH3 (base) - NH4+ (conjugate acid)
NH4+ + CO2
2-↔ NH3 + HCO3-
NH4+ (acid) - NH3 (conjugate base)
CO22- (base) - HCO3
- (conjugate acid)
NH3 + H2S ↔ NH4+ + HS- H2PO4
- + OH- ↔ HPO42- + H2O
H2PO4- (acid) - HPO4
2- (conjugate base)
OH- (base) - H2O (conjugate acid)
NH3 (base) - NH4+ (conjugate acid)
H2S (acid) - HS- (conjugate base)
CONJUGATE
ACID
BASE
Brønsted-Lowry Acid - proton donor - Bronsted-Lowry Base – proton acceptorEvery acid has a conjugate base - Every base has a conjugate acidConjugate acid has one more H than base - Conjugate base has one fewer H than acid.
gain H+
lose H+
lose H+
gain H+
CN-(base) - HCN (conjugate acid)
gain H+
lose H+
lose H+gain H+
lose H+
gain H+
lose H+
gain H+
CH3COOH + H2O ↔ CH3COO- + H3O+
CH3COOH ↔ CH3COO-
H2O ↔ H3O+
Conjugate acid base pair
Conjugate acid base pair
CH3COOH CH3COO-
H2O H3O+Conjugate acid
Conjugate baseAcid
Base
Strong Acid form → Weak Conjugate Base• Strong acid HCI dissociate completely to form Cl− (weak conjugate base)• Cl− weak conjugate base won't accept H+ to form back HCI• HCI + H2O → Cl− + H3O+ (one way)
Bronsted Lowry Conjugate acid base pair
lose H+
gain H+
Acid + Base ↔ Conjugate Base + Conjugate Acid
Brønsted-Lowry Acid - proton donor - Bronsted-Lowry Base – proton acceptorEvery acid has a conjugate base - Every base has a conjugate acidAcid donate proton – Base accept protonConjugate acid has one more H than base - Conjugate base has one fewer H than acid.
Strong acid (HCI) form
weak conjugate base (CI-)
Weak conjugate base (CI) will not accept H+ to form back HCI
Weak Acid form ↔ Strong Conjugate Base• CH3COOH weak acid dissociate partially, form CH3COO- (strong conjugate base)• CH3COO- (strong conjugate base) accept H+ to form back CH3COOH molecule.• CH3COOH + H2O ↔ CH3COO- + H3O+ (reversible)
Weak acid (CH3COOH) form
strong conjugate base (CH3COO-)
Strong conjugate base (CH3COO-) accept H+ form back CH3COOH
Bronsted Lowry Conjugate acid base pair
lose H+
gain H+
Acid + Base ↔ Conjugate Base + Conjugate Acid
Brønsted-Lowry Acid - proton donor - Bronsted-Lowry Base – proton acceptorEvery acid has a conjugate base - Every base has a conjugate acidAcid donate proton – Base accept protonConjugate acid has one more H than base - Conjugate base has one fewer H than acid.
Strong base (NaOH) form
weak conjugate acid (H2O)
Weak conjugate acid (H2O) will not lose H+ to form back OH-
Weak base (NH3) form
strong conjugate acid (NH4+)
Strong conjugate acid (NH4) lose H+ to form back NH3
Strong Base form → Weak Conjugate acid• Strong base NaOH dissociate completely to form OH-
• OH- strong base dissolve in water form H2O (weak conjugate acid) • H2O (weak conjugate acid ) will not lose H+ to form back OH-
• OH- + H2O → H2O + OH- ( one way)
Weak Base form ↔ Strong Conjugate AcidNH3 weak base dissociate partially to form NH4
+ (strong conjugate acid)NH3 + H2O ↔ NH4
+ + OH-
NH4+ (strong conjugate acid) lose H+ to form back NH3
NH3 + H2O ↔ NH4+ + OH- (reversible)
Conjugate Acid
Conjugate Base
H2SO4 HSO4
HCI CI-
H2SO3 HSO3-
HF F-
HNO2 NO2-
CH3COOH CH3COO-
Conjugate Base
Conjugate Acid
OH- H2O
PO43- HPO4
2-
CO32- HCO3
-
NH3 NH4+
Bronsted Lowry Conjugate acid base pair
Strong Base + Acid ↔ Weak Conjugate Acid + Conjugate Base
Strong acid
Weak acid
Weak conjugate base
Strong conjugate base
Strong base
Weak baseStrong conjugate acid
Weak conjugate acid
Strong Acid + Base ↔ Weak Conjugate Base + Conjugate Acid
Weak Acid + Base ↔ Strong Conjugate Base + Conjugate Acid
Weak Base + Acid ↔ Strong Conjugate Acid + Conjugate Base
reversible
reversible
one way
one way
reversible
reversible
reversible
H2O (amphiprotic) - act as acid or base
H2O + HCI ↔ H3O+ + CI-
HCO3- – Base, proton acceptor
HSO4- – Base, proton acceptor
Bronsted Lowry Conjugate Acid base pair
H2O – Acid, proton donor H2O – Base, proton acceptor
HCO3- (amphiprotic) - act as acid or base
HCO3- – Acid, proton donor
H2O + NH3 ↔ NH4+ + OH-
HCO3- + OH- ↔ CO3
2- + H2O HCO3- + H3O+ ↔ H2CO3 + H2O
HSO4- (amphiprotic) - act as acid or base
HSO4- – Acid, proton donor
HSO4- + H2O ↔ H3O+ + SO4
2- HSO4- + HCI ↔ H2SO4 + CI-
Amphiprotic substance :• Act as acid or base • Involve only H+.
• Able to donate H+ or gain H+ ions• All amphiprotic are amphoteric
Amphoteric substance:• Act as acid or base• Does not involve only H+ ions• Al2O3 is amphoteric – No H+ ions• Al2O3 (base) + 6HCI → 2AICI3 + 3H2O
• AI2O3 (acid) + 2NaOH + 3H2O → 2NaAl(OH)4
amphiprotic
amphoteric
gain H+lose H+
lose H+
lose H+
gain H+
gain H+
H+
Amphiprotic – Proton donor (acid)- Proton acceptor (base)
SO2 accept e- CO2 accept e-
Lewis acid Lewis base
CO2 + H2O → H2CO3
H2O donate e-
Lewis acid Lewis base
H2O donate e-
Lewis Acid/Base
Lewis Acid - substance accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance donate electron/lone pair electron donor
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
Lewis Acid Lewis Base
LIKE electron (-ve)Electron deficient – accept lone pair
LIKE nucleus (+ve)Electron rich – donate lone pair
NO2+ Br+SO2 CO2
SO2 + H2O → H2SO3
Molecule asLewis Acid/Base
Molecule acting as Lewis Acid Molecule /Ions as Lewis Base
Lewis Acid/Base
H2O donate e-
HCI + :H2O → CI- + H3O+
HCI accept e-
Lewis acid Lewis base
BF3 + :NH3 → BF3 – NH3
Molecule asLewis Acid/Base
Lewis acid Lewis base
HF accept e-
Lewis acid
HF + H2O → F- + H3O+
H2O donate e-
Lewis baseLewis acid
Lewis Acid - substance accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance donate electron/lone pair electron donorLewis Base - donate electron pair form dative/coordinate bond with Lewis acid
Molecule asLewis Acid/Base
H+ transferDative bond
Dative bond
Dative bond
Electrondonor
Electronacceptor
Electronacceptor
Electrondonor
Electron AcceptorElectron Deficient
Electron donorElectron donorElectron Acceptor
Electron Deficient
NH3 donate e-
BF3 accept e-
F F-
No H+ transfer
BF3 + :F → BF4
F donate e-BF3 accept e-
:F :F
Dative bondLewis base
SO2 + H2O → H2SO3
SO2 accept e- CO2 accept e-Molecule asLewis Acid/Base
Lewis acid Lewis base
Lewis baseLewis acid
H2O + :O2- → 2OH-
O2- donate e-
H2O accept e-
Lewis acid Lewis base
CH3COOH accept e-
CO2 + H2O → H2CO3
H2O donate e-
Lewis acid Lewis base
H2O donate e-
CH3COOH + H2O ↔ CH3COO- + H3O+
H2O donate e-
Lewis Acid/Base
Molecule asLewis Acid/Base
Lewis Acid - substance accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance donate electron/lone pair electron donor
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
Ligand as Lewis Base• lone pair electron
• dative bond with metal
Lewis Acid/Base
Lewis Acid - substance accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance donate electron/lone pair electron donor
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
Lewis Acid Lewis Base
LIKE electron (-ve)Electron deficient – accept lone pair
LIKE nucleus (+ve)Electron rich – donate lone pair
Cu2+
Metal Ion as Lewis Acid•high charge density• empty 3d orbitals
Ni2+ AI3+ Fe3+
Cu2+ + :6H2O → [Cu(H2O)6]2+
Cu2+ accept e-Metal Ion as Lewis Acid
Ligand as Lewis BaseH2O donate e-
Lewis acid
Co2+ + :4CI- → [Co(CI)4]2-
CI- donate e-
Lewis base Lewis acid Lewis base
C02+ accept e-
Co2+
Metal Ion as Lewis AcidLigand as Lewis Base
Lewis baseLewis acid
Fe3+ + :SCN- → [FeSCN]2+
SCN- donate e-
Fe3+ accept e-
H2O donate e-
Fe3+ + 6H2O → [Fe(H2O)]3+
Lewis acid Lewis base
Fe3+ accept e-
AI(OH)3 + :OH- → AI(OH)4-
OH- donate e-
AI3+ accept e-
Lewis baseLewis acid
Ni2+ + :6NH3 → [Ni(NH3)6]2+
NH3 donate e-
Ni2+ accept e-
Lewis baseLewis acid
Lewis Acid/Base
Metal Ion as Lewis AcidLigand as Lewis Base
Lewis Acid - substance accept electron/electron acceptor, empty orbital/electron deficientLewis Base – substance donate electron/lone pair electron donorLewis Base - donate electron pair form dative/coordinate bond with Lewis acid
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
Brønsted-Lowry Acid - substance that donate proton/proton donorBronsted-Lowry Base – substance that accept proton/proton acceptorOne species donate proton – one species accept proton
Arrhenius acid - substance dissociate in water to produce H+ ions.Arrhenius base – substance dissociate in water to produce OH- ions.All Arrhenius acid are Bronsted Lowry acid and water must be present
HCI → H+ + CI-
HCI + H2O ↔ H3O+ + CI-
NaOH→ Na+ + OH-
NH3 + H2O ↔ NH4+ + OH-
CO32- + H2O ↔ HCO3
- + OH-
Water/aqueous medium
Water/aqueous mediumOther solvent medium possible
Definition of Acid and Bases
Arrhenius acid Arrhenius base H+ OH-
2
1
gain H+
Acid + Base ↔ Conjugate Base + Conjugate Acid
lose H+HCI (acid) - CI- (conjugate base)
H2O (base) - H3O+ (conjugate acid)
HCI + H2O ↔ CI- + H3O+
Lewis Acid - accept electron/electron acceptor, empty orbital/electron deficientLewis Base – donate electron/lone pair electron donor.Lewis Base - donate electron pair form dative/coordinate bond with Lewis acid
3
HCI + H2O → CI- + H3O+
H2O donate e-HCI accept e-
Lewis acid Lewis base
gain H+
lose H+
Metal Ion as Lewis Acid• electron acceptor• high charge density• empty 3d orbitals
Ligand as Lewis Base• electron donor • lone pair electron • dative bond with metal
Lewis acid – electrophileLewis base - nucleophileDonation/acceptance electron pair
For following species, state whether it behave as Lewis acid or Lewis base
a) PH3
b) BCI3
c) H2Sd) SF4
e) Cu2+
a) PH3 – P (gp 5) - 1 lone pair electron – electron donor – Lewis baseb) BCI3 – B (gp 3) - electron deficient/incomplete valence shell – electron acceptor – Lewis acidc) H2S – S (gp 6) - 2 lone pair electron – electron donor – Lewis based) SF4 – S (gp 6) - 1 lone pair electron – electron donor – Lewis basee) Cu2+ - (transition metal) – high charge density/incomplete 3d orbital – electron acceptor – Lewis acid
Question Answer
IB Questions
Which acid/base rxn is Lewis Theory and Bronsted Theory?A) NH3 + HCI ↔ NH4CI B) H2O + H2O ↔ H3O
+ + OH- C) Cu2+ + 4NH3 ↔ [Cu(NH3)4]2+ D) BaO + H2O ↔ Ba2+ + 2OH-
A) NH3 + HCI ↔ NH4CI B) H2O + H2O ↔ H3O+ + OH- C) Cu2+ + 4NH3 ↔ [Cu(NH3)4]
2+ D) O2- + H2O ↔ 2OH-
Bronsted Theory Bronsted Theory Lewis Theory Bronsted Theory(H+ transfer) (H+ transfer) (NO H+ transfer) (H+ transfer)
H+H+ H+
Identify Lewis acid and Lewis base
2
1
3
A) Zn2+ + 4NH3 → [Zn(NH3 )4 ] 2+ B) 2CI - + BeCI2 → [BeCI4]2- C) Mg2+ + 6H2O → [Mg(H2O)6]
2+
Lewis acidLewis acid
Lewis acid
Lewis base Lewis base
Lewis base
Lewis Acid/Base
Definition of Acid and Bases
Bronsted – Lowry
Acid/Base
Arrhenius Acid/Base
Arrhenius acid/base• Limited/narrow definition• Only water medium• Substance must have H atom
Bronsted Lowry acid/base• Broader definition • Proton donor/acceptor• Other medium• Substance must have H atom
Lewis acid/base• Broadest definition• Electron acceptor/donor• Substance doesn’t need to have H
All Arrhenius acid are Bronsted Lowry acid All Bronsted Lowry acid are Lewis acid
Click here Bronsted Lowry , Lewis Acid/Base
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3
12
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