TEORI ASAM BASA Asam basa Arrhenius Asam basa Bronsted-Lowry Asam basa Lewis Kesetimbangan asam basa

Acids and Bases Experimental Definitions Asam Rasanya asam Memberikan warna merah pd lakmus Reaksi dg logam menghasilkan gas H2 Reaksi dg basa menghasilkan garam dan air Basa Pahit Memberikan warna biru pd lakmus Reaksi dg asam menghasilkan garam dan air

Some common acids are: Some common bases are: Sulfuric acid (H2SO4) Hydrochloric acid (HCl) Phosphoric acid (H3PO4) Nitric acid (HNO3) Acetic acid (CH3CO2H) Citric acid C3H5O(COOH)3 Some common bases are: Sodium hydroxide (NaOH) Calcium hydroxide [Ca(OH)2] Magnesium hydroxide [Mg(OH)2]

Asam Basa Arrhenius Asam Basa senyawa yg jk dilarutkan + H H O H Asam senyawa yg jk dilarutkan dlm air menghasilkan ion H+ Basa Senyawa jk dlm air menghasilkan ion OH- H - O H - O H - O

H + H H Cl O Cl O H - H H H O - H Na O Na O H + H H - O

Limitations of the Arrhenius Theory 1 Ion H+ dalam air kenyataanya sbg ion hidronium (H3O+) 2 Teori Arrhenius tidak dapat menjelaskan amonia & senyawa lain 3 Reaksi hanya berlaku pada pelarut air

Brønsted-Lowry Theory Asam : donor proton HA(aq) + H2O(l) → H3O+(aq) + A-(aq) Basa : aseptor proton B(aq) + H2O(l) → BH+(aq) + OH-(aq) B-(aq) + H2O(l) → BH(aq) + OH-(aq) Amonia : NH3(aq) + H2O(l) → NH4+(aq) + OH-(aq)

+ + NH3 H2O NH4+ OH- + + H H Asam Basa

Macam Asam  Monoprotic acid Acids with one proton to donate, such as, hydrochloric acid (HCl), nitric acid (HNO3)  Diprotic acid Acids with two protons to donate, such as sulfuric acid (H2SO4)  Triprotic acid Acids with three protons to donate, such as phosphoric acid (H3PO4)

Asam Basa Lewis Asam : aseptor pasangan elektron Basa : donor pasangan elektron F H F H B N B N F + H F H F H F H

Acidic and Basic Anhydrides Some compounds react with water to form acidic or basic solutions. Acidic and basic anhydrides are compounds that react with water to give acids or bases that then donate or accept protons to give acidic or basic solutions. Nonmetal oxides are acidic anhydrides. SO3 + H2O → H2SO4 H2SO4(aq) → 2H+(aq) + SO42-(aq) Metal oxides are basic anhydrides. CaO + H2O → Ca(OH)2 Ca(OH)2(aq) → Ca2+(aq) + 2OH-(aq)

Kesetimbangan asam basa Arrhenius Air merupakan elektrolit lemah dr ionisasi molekul-molekul air itu sendiri → swa-ionisasi (autoionisasi) H H + H H O O H O O - H H H

Air juga dpt berfungsi sbg asam atau kehilangan proton. Bronsted dan Lowry Air juga dpt berfungsi sbg asam atau kehilangan proton. Molekul air yg lain akan berlaku sbg basa utk menerima proton yg digunakan utk membentuk suatu ikatan koordinat kovalen mll sepasang elektron bebas pd atom oksigen menghasilkan ion hidronium (H3O)+ H H + - H + O O + H H O O H H H asam 1 basa 2 asam 2 basa 1

Kesetimbangan ionisasinya aktivitas (α) air = 1

Konsentrasi ion <<<< → konsentrasi molarnya Kw = [H3O+][OH-] Besarnya Kw tergantung pada temperatur pada 25oC [H3O+] = [OH-] = 1,0 .10-7 M Kw air pada 25oC = 1,0 .10-14 M Kw air pada 60oC = 9,6 .10-14 M Kw air pada 100oC = 5,5 . 10-14 M

Asam-basa dlm pelarut air akan mengalami Swa-ionisasi Reaksi ionisasi asam & basa menjadi ion-ionnya H2O + H2O H3O+ + OH- asam basa asam basa HCl + H2O H3O+ + Cl- asam basa asam basa

Kekuatan suatu asam-basa ditentukan berdasarkan derajat ionisasinya Jk terionisasi sempurna → asam-basa kuat Jk hanya sebagian → asam-basa lemah Asam kuat HCl, HBr, HI, HClO4, HNO3, H2SO4 Basa kuat NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

HCl(aq) → H+(aq) + Cl-(aq) HCN(aq) → H+(aq) + CN-(aq) Strong and Weak Acids Strong acids ionize 99,99% in water solution HCl(aq) → H+(aq) + Cl-(aq) Adding 1 mol of HCl to water gives 1 mol of H+ and 1 mol Cl- Weak acids only partially ionize in water solution HCN(aq) → H+(aq) + CN-(aq) Adding 1 mol of HCN to water gives less than 1 mol of H+ and less than 1 mol CN-.

Strong and Weak Acids and Bases Strong bases ionize 99,99% in water solution. NaOH(aq) → Na+(aq) + OH-(aq) Adding 1 mol of NaOH to water gives 1 mol of OH- and 1 mol Na+. Weak bases only partially ionize in water solution NH3(aq) + H2O → NH4 +(aq) + OH-(aq) Adding 1 mol of NH3 to water gives less than 1 mol of NH4+ and less than 1 mol OH-