Acids and Bases Pg. 119

Properties of acids and bases Acidic solutions taste sour Blue litmus paper turns pink when dipped in an acidic solution Basic solutions taste bitter and feel slippery Red litmus paper turns blue when dipped in a basic solution

What makes a solution an acid or a base? All solutions in water contain H ions (H+) and hydroxide ions (OH-) An acidic solution contains more hydrogen ions A basic solution contains more hydroxide ions Neutral solutions contain equal amounts Also use hydronium ions to represent acids (H3O+)

Arrhenius model of Acids and Bases Acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in an aqueous soution Base is a substance that contains hydroxide group and dissociates to produce a hydroxide ion in aqueous solutions Ex Acidic solution : HCl  H+ + Cl- Ex Basic solution: NaOH Na+ + OH-

Bronsted- Lowry model Says an acid is a hydrogen-ion donor and a base is a hydrogen-ion acceptor HX (aq) + H2O (l) H3O+ (aq) + X- (aq) An acid reacting with a base produces a conjugate acid and a conjugate base Conjugate acid is the species that accepts a H+ from an acid Conjugate base is the species that results when an acid gives up a H+. conjugatebase acid base Conjugate acid

Examples identifying acids and bases NH3 (aq) + H2O (l) NH4+ (aq) + OH- (aq) HBr (aq) + H2O H3O+ (aq) + Br –(aq)

Types of acids and bases Water and a few other substances can act as both an acid and a base  called amphoteric Acids that completely ionize are strong acids HCl HBr HI HNO3 HClO4 H2SO4 Acids that ionize partially are weak acids Strong bases dissociate into metal ions and hydroxide

Measuring acids and bases Use the pH scale 0-7 = acidic 7-14 = basic 7 is neutral

Neutralization Acid and a base react to form water and a salt Ex. Mg(OH)2 + 2 HCl  MgCl2 +2 H2O Use titration to determine the concentration at which the solution is neutral