Acids and Bases Chem 332 – O’Dette

Let’s start with WATER!!!! H+ OH- Acid Part Base Part When a water molecule splits, it forms two ions. H+ OH- Acid Part Base Part

Acid Base Theory Arrhenius Svante Arrhenius in 1884 established the first theory of acids and bases Acids produce H+ when dissolved in water Bases produce OH- when dissolved in water EX: HCl – acid NaOH – base

Acid Base Theory Bronsted-Lowry Arrhenius theory doesn’t always work, for example NH3 would be considered an acid by Arrhenius theory but when NH3 reacts it will actually act as a base In 1923 Johannes Bronsted and Thomas Lowry proposed a new acid base theory

Acid Base Theory Bronsted-Lowry (continued) Acid – proton (H+) donor Base – proton (H+) acceptor EX: NH3 + H2O NH4+ + OH- NH3 causes OH- to be generated so it is considered a base and accepted a proton (H+)

Strength of Acids & Bases depends on dissociation Dissociation = acid or base separates into ions in water Acid Ex: HBr (aq) → H+ (aq) + Br- (aq) Base Ex: KOH (aq) → K+(aq) + OH-(aq) 100% dissociation = strong acid/base

Strength of Acids & Bases Strong Acids Hydrochloric (HCl), Nitric (HNO3), Sulfuric (H2SO4) Weak Acids Citric (C6H8O7) & Carbonic (H2CO3) Strong Bases LiOH, NaOH, KOH Weak Bases Baking soda (NaHCO3) & Ammonia (NH3)

Properties of Acids & Bases stingy sour taste turns litmus red phenolphthalein = clear universal indicator = red bromthymol blue = yellow

Properties of Acids & Bases soapy/slippery chalky/bitter taste turns litmus blue phenolphthalein = pink universal indicator = purple bromthymol blue = blue