1. Acids-Bases Part I Arrhenius: Acid…. A substance that increases the hydrogen ion, H +, concentration when dissolved in H 2 O. Eg. HCl, H 2 SO 4, HC 2 H 3 O 2 (CH 3 COOH), etc. Base…. A substance that increases hydroxide ion, OH -, concentration. Eg. NaOH, NH 4 OH, etc. Bronsted-Lowry (1923) (not worried about increasing/decreasing H + or OH - concentrations) Acid … a “proton donor”, p + = H +, any formula HA. Eg. HCl, H 2 SO 4, HC 2 H 3 O 2 (CH 3 COOH), etc. Base …. A “proton acceptor” Eg. OH -, NH 3 ; Cl -

2. Acid solutions: HCl (g) + H 2 O (l) H 3 O + (aq) + Cl - (aq) H 3 O + (aq) = H + (aq) H:Cl:.. + :O::O: H H H H :O::O: H + + :Cl:.. - Hydrogen ion, H +, or hydronium ion, H 3 O + has formed HCl (g) + H 2 O (l) H + (aq) + Cl - (aq)

3. Strength of an acid can be determined by conductivity. 12 M HCl Good or poor electrolyte? Large or small # of ions? HCl (g) + H 2 O (l) H 3 O + (aq) + Cl - (aq)

5. Strength of an acid can be determined by conductivity. Good or poor electrolyte?Large or small # of ions? Pure HC 2 H 3 O 2 Diluted HC 2 H 3 O 2

6. Properties of Acids:

7. Predicting BinaryAcid strength from Periodic Table Position NH 3 H 2 O HF PH 3 H 2 S HCl AsH 3 H 2 Se HBr H 2 Te HI Weaker Stronger Bond energy decreases (size factor) Bond energy decreases EN factor…2 nd element dominates In both cases H separates more easily & acid strength increases

8. Strength of “Oxyacids” (Oxoacids) The more O’s ….the stronger the acid: KaKa HNO 2 4.5 x 10 -4 HNO 3 20 KaKa HClO 3 x 10 -8 HClO 2 1.1 x 10 -2 HClO 3 1 x 10 3 HClO 4 1 x 10 7 Monoprotic acids: Diprotic acids: H 2 SO 3 1.5 x 10 -2 H 2 SO 4 1 x 10 2 Triprotic acids: H 3 PO 4 7.5 x 10 -3 H 2 PO 4 - 6.23 x 10 -8 HPO 4 -2 2.2 x 10 -13

9. More Bronsted-Lowry Acid/Base info: General acid/base reaction: HA + B = A - + HB +

10. Titration problems What is the volume of a 0.325 M NaOH solution needed to just neutralize 65.2 ml of 1.37 M HNO 3 ? Balanced equation: 1 NaOH + 1 HNO 3 = 1 HOH + 1NaNO 3 65.2ml xxxxx = 274.8 = 275ml NaOH

11. Basic Solutions: Strong Arrhenius bases: 1.Group IA hydroxides. Eg. NaOH, KOH 2.Lower Group IIA hydroxides. Eg. Sr(OH) 2, Ba(OH) 2

12. More Bronsted-Lowry Acid/Base info: Bases react with water to produce OH -

13. Hydrolysis Salt + H 2 O  Acidic solution Neutral solution Basic solution

14. NaClO + H 2 O : Predicted base and acid: NaOH vs HClO

15. Lewis Acid/Base Lewis acid: electron pair acceptor Lewis base: electron pair donor H+H+ + :N:.. H H H Lewi s acid Lewis base.. H H H H ::N + “adduct” … the product of a L.acid/base rx