Acid Base Chemistry

How to test if a solution is an acid or a base

  • Taste

  • Litmus paper

  • pH meter(most accurate)

  • Electrical conductivity

    • Strong acid and base are more conductive

Properties

  • Concentration: amount of substance in solution, measured in mol/L

  • Strength: depends on the amount of dissociation

Acids

  • ↑[H3O] = ↑Acid concentration

  • Strong acids dissociate completely in solution(water)

    • Therefore high [H3O] = low pH

  • Weak acids dissociate partially

    • Therefore low [H3O] = high pH

Acids

  • Ex) HCl

  • Most acids start with H+

    • Can also end with -COOH

  • Corrosive

  • Turns litmus red

  • Taste sour

  • Conductive

  • Reacts with metals

  • pH <7

  • ↑[H3O] = ↑Acid concentration

Base

  • Ex)NaOH

  • Usually starts with a metal and ends with OH-

  • Corrosive

  • Turns litmus blue

  • Bitter

  • Conductive

  • pH >7

  • ↑[OH] = ↑Base concentration


Neutralization

  • To neutralize a strong acid, we use a weak base

  • To neutralize a strong base, we use a weak acid


Arrhenius acids and bases

  • Dissociation/ionization: Separation of a chemical substance into its individual ions

  • Acids

    • Compounds that dissociate in solutions to form hydrogen ions(H+)

  • Neutral compounds

    • Compounds that don’t dissociate in solution to form hydrogen(H+) or hydroxide(OH-)

  • Bases

    • Compounds that dissociate in solution to form hydroxide ions(OH-)

Bronsted and Lowry definition of acids and base

  • Acids - proton donor

  • Bases - proton acceptor

    • Proton = hydrogen ion(H+)

Buffers

  • A substance that resists change in pH(H3O+ ions) when exposed to an acid and a base

    • Ex) Carbonate ions(CO3 2-)