Describing Acids and Bases Properties of Acids and Bases Acids Produce H+ ions when dissolved in water Sour taste Solutions are electrolytes (some strong, some weak) React with metals to produce H2 React with a base to form water and salt Turn litmus paper red

Describing Acids and Bases Produce OH- ions when dissolved in water Bitter taste Feel slippery Solutions are electrolytes (strong and weak) React with acids to form water and a salt Turn litmus paper blue

What are acids and bases? Arrhenius Acids Hydrogen-containing compounds that ionize to yield hydrogen ions (H+) in aqueous solutions Arrhenius Bases Compounds that ionize to yield hydroxide ions (OH-) in aqueous solutions

What are acids and bases? Bronsted-Lowry Acid A hydrogen-ion donor Bronsted-Lowry Base A hydrogen-ion acceptor

Describing Acids and Bases Names and formulas of acids and bases Acids Acids have a hydrogen ion The general formula for an acid is HX, where the X is a monatomic or polyatomic ion Bases Bases usually have an OH- ion Ionic compounds that are bases are named like any other ionic compound There are exceptions like ammonia which is NH3

Hydrogen Ions and Acidity The pH concept Expressing concentration in molarity is inefficient, so we use a pH scale The scale ranges from 0 to 14 0 is very acidic, 7 is neutral, and 14 is very basic The pH of a solution is the negative logarithm of the hydrogen-ion concentration pH = -log [H+], [H+] = 2nd log (-) pH The pOH of a solution equals the negative logarithm of the hydroxide-ion concentration pOH = -log[OH-], [OH-] = 2nd log (-) pOH pH + pOH = 14