1. Acid-Base Reactions

2. Acids Molecules that ionize in water to form hydrogen ions (H + ) Acids donate [GIVE AWAY] hydrogen ions (H + ) (protons). PROTON DONOR HCl  H + + Cl – HNO 3  H + + NO 3 –

3. Acid-Base Reactions Bases Substances that form hydroxide ions (OH - ) in aqueous solutions: NaOH  Na + + OH – NH 3 + H 2 O  NH 4 + + OH – Bases accept [TAKE] hydrogen ions (H + ) (protons). PROTON ACCEPTOR

4. Strong and Weak Acids and Bases Strong acids are strong electrolytes: They completely ionize in aqueous solution HCl (s)  H + + Cl –

5. Strong Acids - MEMORIZE Sulfuric Acid H 2 SO 4 Nitric Acid HNO 3 Hydrochloric Acid HCl Hydrobromic Acid HBr Hydroiodic Acid HI Chloric Acid HClO 3 Perchloric Acid HClO 4 Battery acid Used to make fertilizers and explosives Stomach Acid Used in manufacturing Used in manufacturing & to make meth Used in manufacturing Used to make rocket fuel

6. Strong Bases - MEMORIZE GROUP 1A HYDROXIDES (LiOH, NaOH, KOH, RbOH, CsOH) Examples: Sodium hydroxideNaOHlye or caustic soda Potassium hydroxideKOHlye or caustic potash GROUP 2A HYDROXIDES* (Only Ca(OH) 2, Sr(OH) 2, Ba(OH) 2 ) “CBS” hydroxides are only slightly soluble in water. However, the part that dissolves is 100% ionized, therefore they are considered strong bases.

7. Review: Electrolyte: Aqueous solutions containing ions

8. Strong and Weak Acids and Bases Weak acids are weak electrolytes: They ionize only slightly in aqueous solution. H 2 CO 3 (aq)  H + + HCO 3 

9. Strong and Weak Acids and Bases Strong bases are strong electrolytes: They completely ionize in aqueous solution into metal ions and hydroxide ions (OH - ). Weak bases are strong electrolytes: They ionize only slightly in aqueous solution.

10. Neutralization Reactions – Double Replacement Reactions When an acid reacts with a base, it is called NEUTRALIZATION REACTION. “Driving force” is the formation of water. In a NEUTRALIZATION REACTION the products are water and a salt.

11. Neutralization Reactions – Strong Acid & Strong Base When a strong acid reacts with a base, the net ionic equation is… HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l) acid + base  salt + water H + + Cl - + Na + + OH -  Na + + Cl - + H 2 O (l) H + + OH -  H 2 O (l)

12. Neutralization Reactions – Weak Acid & Strong Base When a weak acid reacts with a strong base, the net ionic equation is… 2 CH 3 COOH (aq) + Ba(OH) 2 (aq)  Ba ( CH 3 COO ) 2 (aq) + 2H 2 O (l) Weak acids do not completely dissociate, so the complete ionic equation is: 2 CH 3 COOH (aq) + Ba 2+ +2 OH -  Ba 2+ + 2 CH 3 COO - + H 2 O (l) and the net ionic equation is: 2 CH 3 COOH (aq) + 2OH -  CH 3 COO - + H 2 O (l)

13. Neutralization Reactions – Strong Acid & Solid Base When an acid reacts with a solid base, the net ionic equation is… 2 HCl (aq) + Mg(OH) 2  MgCl 2 + 2 H 2 O (l) 2 H + + 2 Cl - + Mg(OH) 2 (s)  Mg 2+ + 2 Cl - + 2 H 2 O (l) 2 H + + Mg(OH) 2 (s)  Mg 2+ + 2 H 2 O (l) (s)(s) (aq)

14. Acid Base Gas-Forming Reactions – Double Replacement Reactions Some acid reactions form gases that leave the system (preventing re-formation of the reactants). CaCO 3 (s) + 2 HCl (aq)  CaCl 2 (aq) + H 2 CO 3 (aq) But H 2 CO 3 will decompose: H 2 CO 3 (aq)  CO 2 (g) + H 2 O (l) CaCO 3 (s) + 2 HCl (aq)  CaCl 2 (aq) + CO 2 (g) + H 2 O (l)

15. Acid Base Gas-Forming Reactions MEMORIZE: If your product is:It will immediately turn into: H 2 CO 3  CO 2 (g) + H 2 O (l) H 2 S  H 2 S (g) * Rotten egg smell NH 4 OH  NH 3 (g) + H 2 O (l) Some acid reactions form gases that leave the system (preventing re-formation of the reactants).

16. Acid Base Gas-Forming Reactions Example: Strontium sulfide reacts with hydroiodic acid SrS (s) + 2 HI (aq)  H 2 S (g) + SrI 2 (aq) The complete ionic equation is: SrS (s) + 2 H + + 2I -  H 2 S (g) + Sr 2+ + 2I - The net ionic equation is: SrS (s) + 2 H +  H 2 S (g) + Sr 2+

17. Acid Base Gas-Forming Reactions Example: Ammonium chloride reacts with sodium hydroxide NH 4 Cl (s) + NaOH (aq)  NH 4 OH + NaCl (aq) But NH 4 OH will decompose: NH 4 OH  NH 3 (g) + H 2 O (l) NH 4 Cl (s) + NaOH (aq)  NaCl (aq) + NH 3 (g) + H 2 O (l) http://www.youtube.com/watch?v=LUEakMDNRsM

18. Review Is a proton (H + ) donor an acid or a base? Acid Is a proton (H + ) acceptor an acid or a base? Base

19. Review Proton (H + ) donor or Proton (H+) acceptor Acid Base HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l) HCl is the acid and NaOH is the base Strong acids (low pH) dissociate (“break apart”) into: Hydrogen ion and the anion

20. Review Strong bases (high pH) dissociate (“break apart”) into: Hydroxide ion and the cation Strong acids form _________ ions hydrogen ions (H + ) Strong bases form _________ ions hydroxide ions (OH - )