Acid and Base Reactions Shireen Rudina ingegneria biologica Equipe de dibattito Arrhenius Theory In water, acids dissociate to form H+ and bases dissociate to form OH- HCl + H 2 O H 3 O + + Cl - Concept Q: Which of these options are only acids? 1. HCl, NH 3, HI 2. H 2 CO 3, NaOH, HBr 3. H 2 CO 3, NH 4 +, HCl 4. HI, KOH, HBr Arrhenius Strong/Weak Acids Strong acid Dissociates completely Weak acids- everything else CH 3 COOH (aceto) NH 4 + HCl HNO 3 H 2 SO 4 HBr HI HClO 4 Arrhenius Strong/Weak Bases Strong bases: LiOH NaOH KOH RbOH CsOH Ba(OH) 2 Ca(OH) 2 Sr(OH) 2 Weak bases: everything else In teams: Calculate the pH of a 0.05 M HBr solution 1.Is HBr a strong acid? How much does it dissociate? 2.What is [H+]? In teams: A M solution of uric acid (HC 5 H 3 N 4 O 3 ) has a pH of Calculate the K a of uric acid. 1.What is the equation for K a ? 2.What variables do we have? sDosDomp0mp0183neutral.html183neutral.html In teams: You have an unknown acid. When you put 1 M in water, you see a pH that corresponds to a specific dissociation percentage. Find the Ka for the acid that dissociates: Team 1: 1% Team 2: 2% Team 3: 0.1% What acid do you have? Arrhenius Acid/Base Reaction Acid + Base = Salt + Water HBr + NaOH NaBr + H 2 O Neutralization Phenolphthalein: Purple if pH > 7 Colorless if pH H 2 CO 3 Ca(OH) 2 + H 2 CO 3 --> CaCO HOH What is the result of a neutralization reaction: NaOH + H 2 CO 3 ? 1.NaH 2 + H 2 O 2.NaH 2 + H 2 O + CO 3 3.NaHCO 3 + H 2 O 4.NaCO 3 + H 2 O Bronsted-Lowry Acid/Base Reaction Conjugate acids and bases