Acids & Bases Acids: acids are sour tasting Arrhenius acid: Any substance that, when dissolved in water, increases the concentration of hydronium ion (H3O+) Bronsted-Lowry acid: A proton donor Lewis acid: An electron acceptor Bases: bases are bitter tasting and slippery Arrhenius base: Any substance that, when dissolved in water, increases the concentration of hydroxide ion (OH-) Bronsted-Lowery base: A proton acceptor Lewis acid: An electron donor

ELECTROLYTES Electrolytes are species which conducts electricity when dissolved in water. Acids, Bases, and Salts are all electrolytes. Salts and strong Acids or Bases form Strong Electrolytes. Salt and strong acids (and bases) are fully dissociated therefore all of the ions present are available to conduct electricity. HCl(s) + H2O  H3O+ + Cl- Weak Acids and Weak Bases for Weak Electrolytes. Weaks electrolytes are partially dissociated therefore not all species in solution are ions, some of the molecular form is present. Weak electrolytes have less ions avalible to conduct electricity. NH3 + H2O  NH4+ + OH-

Acids & Bases STRONG vs WEAK H2SO4 NaOH HI KOH HBr Ca(OH)2 HCl Sr(OH)2 _ completely ionized _ partially ionized _ strong electrolyte _ weak electrolyte _ ionic/very polar bonds _ some covalent bonds Strong Acids: Strong Bases: HClO4 LiOH H2SO4 NaOH HI KOH HBr Ca(OH)2 HCl Sr(OH)2 HNO3 Ba(OH)2

Acids & Bases a. Al(OH)3 + HCl  b. Ba(OH)2 + HC2H3O2  For the following identify the acid and the base as strong or weak . a. Al(OH)3 + HCl  b. Ba(OH)2 + HC2H3O2  c. KOH + H2SO4  d. NH3 + H2O  Weak base Strong acid Strong base Weak acid Strong acid Strong base Weak acid Weak base

Acids & Bases a. Al(OH)3 + HCl  b. Ba(OH)2 + HC2H3O2  For the following predict the product. To check your answer left click on the mouse. Draw a mechanism detailing the proton movement. a. Al(OH)3 + HCl  b. Ba(OH)2 + HC2H3O2  c. KOH + H2SO4  d. NH3 + H2O  3 AlCl3 + 3 H2O 2 Ba(C2H3O2)2 + 2 H2O K2SO4 + 2 H2O 2 NH4+ + OH-

Acids & Bases a. Al(OH)3 + 3 HCl  AlCl3 + 3 H2O For the following Identify the conjugate acid and the conjugate base. The conjugate refers to the acid or base produced in an acid/base reaction. The acid reactant produces its conjugate base (CB). a. Al(OH)3 + 3 HCl  AlCl3 + 3 H2O b. Ba(OH)2 + 2 HC2H3O2  Ba(C2H3O2)2 + 2 H2O c. 2 KOH + H2SO4  K2SO4 + 2 H2O d. NH3 + H2O  NH4+ + OH- CA CB CB CA CB CA CA CB

pH A measure of the hydronium ion The scale for measuring the hydronium ion concentration [H3O+] in any solution must be able to cover a large range. A logarithmic scale covers factors of 10. The “p” in pH stands for log. A solution with a pH of 1 has [H3O+] of 0.1 mol/L or 10-1 A solution with a pH of 3 has [H3O+] of 0.001 mol/L or 10-3 A solution with a pH of 7 has [H3O+] of 0.0000001 mol/L or 10-7 pH = - log [H3O+]

The pH scale pH = - log [H3O+] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 The pH scale ranges from 1 to 10-14 mol/L or from 1 to 14. pH = - log [H3O+] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 acid neutral base

pH + pOH = 14 ; the entire pH range! Manipulating pH Algebraic manipulation of: pH = - log [H3O+] allows for: [H3O+] = 10-pH If pH is a measure of the hydronium ion concentration then the same equations could be used to describe the hydroxide (base) concentration. [OH-] = 10-pOH pOH = - log [OH-] thus: pH + pOH = 14 ; the entire pH range!

PRACTICE PROBLEMS 3. What is the molar concentration of hydronium ion in a solution of pH 8.25? 4. What is the pH of a solution that has a molar concentration of hydronium ion of 9.15 x 10-5? 5.623 x 10-9 M pH = 4.0