Pg

◦ Tastes sour ◦ Corrosive to metals ◦ Electrolytes: break into ions when dissolved in water ◦ React with blue litmus and indicators

◦ Taste bitter ◦ Eat through organic material ◦ Electrolytes ◦ React with red litmus paper and indicators

 First person to have some understanding of acids and bases was Svante Arrhenius ◦ Acids – produce hydrogen ions in aqueous solutions. ◦ Bases – produce hydroxide ions in aqueous solutions.

HCl (g) H + (aq) + Cl - (aq) NaOH (s)Na + (aq) + OH - (aq) HNO 3 HC 2 H 3 O 2 KOH

 The theory is limited ◦ Only one kind of base  must produce OH - !  Ammonia (NH 3 ) is a base, but it doesn’t produce OH - …

 In the Bronsted-Lowry definition: ◦ Acid – hydrogen ion (proton) donor ◦ Base – hydrogen ion (proton) acceptor General formula: HA(g) + H 2 O(l)  H 3 O + (aq) + A - (aq) acid base

 This broadens the definition ◦ The acid or base doesn’t need to be in water ◦ Bases don’t need to contain an OH - ◦ All acids and bases defined by the Arrhenius model are also acids and bases in the Bronsted - Lowry model

 HCl(aq) + H 2 O(l)  H 3 O + (aq) + Cl -  What is the name of H3O + ? ◦ Hydronium ion  What is the acid? ◦ HCl  What is the base? ◦ Water

 Conjugate acid-base pairs: NH 3 (aq) + H 2 O(l)  NH 4 + (aq) + OH - (aq) Base acidconjugate conjugate acid base Conjugate acid – the particle formed when a base gains an H + ion. Conjugate base – the particle that remains after the acid donates an H + ion.

 Which of the following represent conjugate acid-base pairs? A) HClO 4, ClO 4 - B) HCl, ClO - C) H 2 PO 4 -, HPO 4 2- D) HNO 3, NO 3 - A, C, and D