Acids and Bases Definitions and Properties

Acidic or Basic?

Common Acids and Bases Strong acids/bases – 100% dissociation into ions Weak acids/bases – partial dissociation, both ions and molecules Strong Acids (strong electrolytes) HClhydrochloric acid HNO 3 nitric acid HClO 4 perchloric acid H 2 SO 4 sulfuric acid Weak Acids (weak electrolytes) CH 3 COOHacetic acid H 2 CO 3 carbonic Strong Bases (strong electrolytes) NaOH sodium hydroxide KOH potassium hydroxide Ca(OH) 2 calcium hydroxide Weak Base (weak electrolyte) NH 3 ammonia NH 3 + H 2 O  NH 4 OH

 It is still a singly charged nuclear particle.  But, typically it refers to H+, a hydrogen atom stripped of its electron and, thus, in its ionic form.  One adds a proton to a base: add H and one unit of positive charge.  One removes a proton from an acid: subtract H and one unit of positive charge. In the Context of Acids and Bases, What is a Proton?

HA H+H+ A-A- Strong Acid 100% dissociation of HA Would the solution be conductive?

HA H+H+ A-A- Weak Acid HA  H + + A - At any one time, only a fraction of the molecules are dissociated.

Steps on the pH scale represents a 10X change. It’s a logarithmic scale.. pH 5 vs. pH 6 (10X more acidic) pH 3 vs. pH 5 (100X different) pH 8 vs. pH 13 (100,000X different) pH Scale Measures Acidity/Basicity ACIDBASE NEUTRAL

Acid Base pH = -log [H + ] [H + ] is the concentration of the H + ion in solution pH = 7 Acidic Basic Neutral [H + ] [OH - ] [H + ] = [OH - ]

pH of Common Substances 1.0 M HCl 0 gastric juice 1.6 vinegar 2.8 carbonated beverage 3.0 orange 3.5 apple juice 3.8 tomato 4.2 lemon juice 2.2 coffee 5.0 bread 5.5 soil 5.5 potato 5.8 urine 6.0 milk 6.4 water (pure) 7.0 drinking water 7.2 blood 7.4 detergents bile 8.0 seawater 8.5 milk of magnesia 10.5 ammonia 11.0 bleach M NaOH (lye) acidic neutral basic [H + ] = [OH - ]

Common Acids Sulfuric AcidH 2 SO 4 Nitric AcidHNO 3 Phosphoric AcidH 3 PO 4 Hydrochloric AcidHCl Acetic Acid CH 3 COOH Carbonic Acid H 2 CO 3 Battery acid Used to make fertilizers and explosives Food flavoring Stomach acid Vinegar Carbonated water

Common Bases Sodium hydroxideNaOHlye or caustic soda (Drano) Potassium hydroxideKOHlye or caustic potash Magnesium hydroxideMg(OH) 2 milk of magnesia Calcium hydroxideCa(OH) 2 slaked lime Ammonia waterNH 3 H 2 Ohousehold ammonia Name Formula Common Name NH 4 OHNH OH - ammonium hydroxide

Arrhenius Acids and Bases Acids release hydrogen ions in water. Bases release hydroxide ions in water. An acid is a substance that produces hydronium ions, H 3 O +, when dissolved in water. Lewis Definitions A Lewis acid is a substance than can accept (and share) an electron pair. A Lewis base is a substance than can donate (and share) an electron pair. Lewis Acid Brønsted-Lowry Definitions A Brønsted-Lowry acid is a proton donor; it donates a hydrogen ion, H +. A Brønsted-Lowry base is a proton acceptor; it accepts a hydrogen ion, H +. Brønsted- Lowry A Acid/Base Definitions

Acid – Base Systems TypeAcidBase ArrheniusH + or H 3 O + producer OH - producer Brønsted- Lowry Proton (H + ) donor Proton (H + ) acceptor LewisElectron-pair acceptor Electron-pair donor

Definitions  Arrhenius - In aqueous solution… HCl + H 2 O  H 3 O + + Cl – –Acids form hydronium ions (H 3 O + ) H HHHH H Cl OO – + acid

Definitions  Arrhenius - In aqueous solution… Bases form hydroxide ions (OH - ) NH 3 + H 2 O  NH OH - H H H H H H N NO O – + H H H H base

Definitions  Brønsted-Lowry HCl + H 2 O  Cl – + H 3 O + –Acids –Acids are proton (H + ) donors. –Bases –Bases are proton (H + ) acceptors. conjugate acid conjugate base baseacid

Water is Amphoteric base acid CA CB NH 3 + H 2 O NH OH - HCl + H 2 O H 3 O + + Cl - acid base CA CB Amphoteric Substances Amphoteric Substances: Substances which can act as either proton donors (acids) or proton acceptors (bases) depending on what substances are present.

Definitions H 2 O + HNO 3  H 3 O + + NO 3 – CBCAAB H H O HO O O N Base Acid

Definitions NH 3 + H 2 O  NH OH - CACBBA H H O H N Base Acid H H

Conjugate Bases for Acids F - H 2 PO 4 - H2OH2O HF H 3 PO 4 H 3 O +  Give the conjugate base for each of the following: - an acid with more than one H +  Polyprotic - an acid with more than one H +

Conjugate Acids for Bases Br - HSO 4 - CO 3 2- HBr H 2 SO 4 HCO 3 -  Give the conjugate acid for each of the following: Courtesy Christy Johannesson

Neutralization ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H 2 O HC 2 H 3 O 2 + NaOH  NaC 2 H 3 O 2 + H 2 O Salts can be neutral, acidic, or basic. Neutralization does not mean pH = 7. weak strong neutral basic Neutralization is a chemical reaction between an acid and a base to produce a salt (ionic compound) and water.

Examples of everyday uses of neutralization Shampoo (a mild alkali) and conditioner (a mild acid) Toothpaste (alkaline) neutralizes acids produced by bacteria Wasp sting (alkaline) and vinegar to relieve pain Acidic soil neutralize by adding calcium hydroxide (lime)

phosphoric acid ammonium hydroxide ammonium phosphate Reactions that Produce Salt (Double Replacement Reactions) acid + base salt +water H 3 PO 4 NH 4 OH (NH 4 ) 3 PO 4 H2OH2O nitric acid magnesium hydroxide magnesium nitrate HNO 3 Mg(OH) 2 Mg(NO 3 ) 2 H2OH2O carbonic acid potassium hydroxide potassium carbonate H 2 CO 3 KOH K 2 CO 3 H2OH2O acetic acid aluminum hydroxide aluminum acetate HC 2 H 3 O 2 Al(OH) 3 Al(C 2 H 3 O 2 ) 3 H2OH2O perchloric acid barium hydroxide barium perchlorate HClO 4 Ba(OH) 2 Ba(ClO 4 ) 2 H2OH2O + + water