1 / 9

STRONG BASES LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH) 2 , Sr(OH) 2 , Ba(OH) 2

STRONG BASES LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH) 2 , Sr(OH) 2 , Ba(OH) 2. Equations for Strong Arrhenius bases - ionize completely to form OH - LiOH (s) → Li + + OH - Ca(OH) 2 (s) → Ca 2+ + 2 OH -. Calculate the pH of 0.15M Calcium hydroxide solution.

hamish-preston
Download Presentation

STRONG BASES LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH) 2 , Sr(OH) 2 , Ba(OH) 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. STRONG BASES • LiOH, NaOH, KOH, RbOH, CsOH, • Ca(OH)2, Sr(OH)2, Ba(OH)2 Equations for Strong Arrhenius bases - ionize completely to form OH- LiOH (s) → Li+ + OH - Ca(OH)2 (s) → Ca2+ + 2 OH - Calculate the pH of 0.15M Calcium hydroxide solution.

  2. Weak Acids & Bases Equations for dissociation ( produce OH- by equilibrium dissociation) 1. Weak OH- bases Fe(OH)3(s) Fe 3+(aq) + 3 OH-(aq) 2. Weak NH3 bases NH3 (aq) NH4+(aq) + OH-(aq) 3. Conjugate of weak acid-bases: OCl-(aq) HOCl (aq) + OH- (aq) Base Dissociation Constant: Kb Kb = [NH4+] [OH-] NH3(aq) + H2O ↔OH- (aq) + NH4+ (aq) [NH3]

  3. Write the dissociation equation and the Kb expression for the reaction of each base with water: • Propyl amine, C3H7NH2 • Monohydrogen phosphate ion, HPO42- • Benzoate ion, C6H5CO2- • Calculate the molar concentration of OH-ions in a 1.15M solution of hypo bromite ion, BrO-, Kb = 4.0 x 10-6. What is the pH?

  4. Weak Base Problem solving with % Ionization Weak Base Problem #2 Ammonia is a weak base that dissociates in water with a dissociation constant, Kb = 1.8 x 10-5 : NH3 + H2O  NH4+ + OH- I C E • Determine the hydroxide ion concentration and the % dissociation of 0.150M solution of ammonia. • Determine the pH of a solution prepared by adding 0.0500 mole of solid ammonium chloride to 100 ml of 0.15M ammonia.

  5. I. Arrhenius Acids form H3O+, Bases form OH- HCl H3O + + Cl- Ca(OH)2 Ca2+ + 2 OH- • Bronsted-Lowry Acids donate protons Bases accept protons HF + OH- F- + H2ONH3 + H2O  NH4+ + OH- • Lewis Acids are electron pairBases are electron pair acceptors donors Zn2+ (aq) + 4H2O : Zn(H2O)42+ (aq) acidbase

  6. Identifying Acids & Bases • Write the formula, identify as • Arrehnius, B-L, Lewis • Acid or Base • Write the conjugate partner: • Write the acid equation: • Write the base equation:

  7. Chalkboard Races Write the following net ionic equations, guess the pH when 1 M solutions are mixed. NH3 C6H5COOH NaOH + HNO3 NaOH + CH3COOH Mg(OH)2 H3PO4 HCl + KOH HCl + NH3

  8. Writing Net Ionic Acid-Base Reactions • 1. Strong acid - strong base: • net: H+(aq) + OH-(aq)  H2O • 2. Strong base - weak acid (HF + Ca(OH)2 ) • net: HF(aq) + OH- H2O + F-(aq) • 3. Strong acid - weak base ( HCl + NH3 ) • net: H+(aq) + NH3(aq)  NH4+(aq) • *In each case, the species present at highest concentrationis written • * Weak or insoluble are written as molecular, • strong or soluble are written as ions. • Notice that salts of weak acids will form basic solutions, • and salts of weak bases will form acidic solutions.

  9. Polyprotic Acids Polyprotic Acids When acid has more than one hydrogen proton, it will have more than one Ka. Ka1 = the dissociation constant for the first proton, will be much larger Ka2 = second dissociation constant, much lower than the first. Example: H2S  H+ + HS- HS-  H+ + S-2 The total Ka for a polyprotic acid is Ka1 x Ka2 = [H+][HS-] [H+][S2-] [H2S] [HS-] which results in an overall Ka= [H+]2 [S2-] [H2S] Ka1 = [H+][HS-] Ka1 = [H2S] Ka2 = [H+][S2-] Ka2 = [HS-]

More Related