ACIDS AND BASES CHAPTER 19 Pages

Properties of Acids Acids have a SOUR taste Turn blue litmus paper RED Conduct electricity React with metals to produce H 2 gas (Single Replacement reaction) Form H + ions in water pH < 7.0

Acids ( continued) React with BASES to produce a salt & H 2 O (aka a DOUBLE REPLACEMENT & NEUTRALIZATION REACTION) Remember: A salt is an ionic compound, a metal and non-metal. An electrolyte is a substance which conducts electric current.

ALL ACIDS MUST CONTAIN HYDROGEN

Acids containing only one hydrogen are called Monoprotic, Ex: HNO 3 diproticAcids with two hydrogens are diprotic, EX: H 2 SO 4 & H 2 CO 3 polyAcids with 2 or more are polyprotic, EX: H 3 PO 4

ACID NOMENCLATURE Binary- contain 2 different elements Hydrogen and one other element Binary acids begin with HYDRO Hydro + root word of 2 nd element + IC

Examples of Binary Acids HF - Hydrofluoric HCl - Hydrochloric HBr - Hydrobromic HI - HydroIodic H 2 S - Hydrosulfuric

OXY acids Contain OXYGEN hydrogen one other non metal

OXY acid nomenclature Named after POLYATOMIC ion they contain (…ate or …ite) RECALL: “If I ate an acid, it would make me sick” “Dynamite is dangerous”

HERE WE GO!! HNO 3 (nitrate) HNO 2 (nitrite) Nitric Nitrous H 2 SO 4 (sulfate) H 2 SO 3 (sulfite) Sulfuric Sulfurous H 3 PO 4 (phosphate H 3 PO 3 (phosphite) Phosphoric Phosphorous

Oxyacid nomenclature …. HC 2 H 3 O 2 or CH 3 COOH (acetate) acetic acid when diluted it is known as vinegar H 2 CO 3 (carbonate) carbonic acid

Arrhenius & Bronsted-Lowry Acids & Bases

According to Arrhenius …. An acid is a substance that contains hydrogen & ionizes to produce hydrogen ions (H + ) in aqueous solution. An base is a substance that contains a hydroxide group and dissociates to produce hydroxide ions (OH - ) in aqueous solution.

Arrhenius acid: HCl (g) → H + (aq) + Cl - (aq) the HCl ionizes to produce H + ions which makes the solution acidic. Arrehenius base NaOH (s) → Na + (aq) + OH - (aq) the NaOH ionizes in water to produce OH - ions to make the solution basic.

According to Bronsted-Lowry… An acid is a hydrogen ion or proton donor A base is a hydrogen- ion or proton acceptor

Conjugate Acid Base Pairs A conjugate acid-base pair consists of two substance related to each other by the donating and accepting of a single hydrogen ion.

Let’s compare! The conjugate acid is the species formed when a base accepts a hydrogen ion from an acid. The conjugate base is the species that results when an acid donates a hydrogen ion to a base.

Let’s Practice Do the practice problems on page 599 of text

Strong acids Strong acids ionize completely in water: that means that their ions remain as ions in water Weak acids do NOT ionize completely in water: that means that their ions react to reform their acid in a reversible reaction.

See page 603 for examples of strong and weak acid reactions. Notice the double arrows Indicating a reversible reaction.

Strong acids do NOT produce a reversible reaction. Weak acids DO produce a reversible reaction.

Strong Acids HCl → H + + Cl – H 2 SO 4 → 2H + + SO 4 -2 HNO 3 → H + + NO 3 - (note only one arrow in one direction)

WEAK ACIDS Produce reversible reactions Equilibrium reactions H 3 PO 4 3H + + PO 4 -3 HC 2 H 3 O 2 H + + C 2 H 3 O 2 - (CH 3 COOH) H 2 CO 3 2H + + CO 3 -2

Why Acids? Acids are important in industry and manufacturing processes. H 2 SO 4 -the most commonly produced chemical in the world. Used in petroleum cracking, production of dyes, fertilizers, paints, paper, detergents. Car batteries Dehydration agent (removal of H 2 O)

HNO 3 Used in making dynamite, explosives (TNT) Used in making rubber, plastics, dyes, & pharmaceuticals H 3 PO 4 Flavoring agent in beverages

HCl - Stomach acid used in digestion process to break up and dissolve food particles & to kill unwanted bacteria Commercially used as a cleaning agent, sold at Home Depot as Muriatic Acid, used to clean brick & concrete. (This is the yellow, sour stuff when you throw up!)

HC 2 H 3 O 2 or CH 3 COOH diluted 1:10 to make vinegar A carboxyl acid, because the COOH is called a carboxyl group. It is at the end of a long chain of hydrocarbons. CH 3 C = O - OH

Self Ionization of Water H 2 O + H 2 O ↔ H 3 O + + OH - {H 3 O + } = Concentration of hydronium ions is 1 x M {OH - } = Concentration of hydroxide ions is 1 x M

Ionization constant (K) for water K w = {H 3 O + } {OH - } = 1 x M 2 (1 x M) (1 x M) = 1 x M 2

pH- The letters “pH” originated in France and mean “the power of Hydrogen” Numerically pH is the negative of the common (base 10) logarithm of the hydronium ion. pH = - log {H 3 O + } pOH = -log {OH - }

Practice Problem A 1.0 x M solution of HNO 3 has been prepared for a laboratory experiment. a) Calculate the {H 3 O + } of this solution. b) Calculate the {OH - }.

Numerically pH & pOH are the negative of the common (base 10) logarithm of the hydronium & hydroxide ions. pH = - log {H 3 O + } -log of 1 x = -(-7) = 7 pOH = -log {OH - } -log of 1 x = -(-7) = 7