Properties of Acids (Begin with Hydrogen) taste sour…the word 'acid' comes from the Latin acere, which means 'sour' acids change litmus (a blue vegetable dye) from blue to red their aqueous (water) solutions conduct an electric current react with bases to form salts and water evolve hydrogen gas (H 2 ) upon reaction with an active metal Corrodes metals Properties of Bases (Ends with Hydroxide) taste bitter feel slippery or soapy bases don't change the color of litmus; they can turn red (acidified) litmus back to blue their aqueous (water) solutions conduct an electric current react with acids to form salts and water

General properties ACIDS Taste sour Turn litmus Reacts with active metals – Fe, Zn, Mg React with bases to form salts and water Hydronium Ion present (H 3 O) + BASES Taste bitter Turn litmus Feel soapy or slippery (react with fats to make soap) React with acids to form salts and water Hydroxide Ion present (OH) - blue to redred to blue

Acid/Base Definitions Acids – produce H + Bases - produce OH - Acids – donate H + Bases – accept H + Acids – accept e - pair Bases – donate e - pair Arrehenius Bronsted-Lowry Lewis only in water any solvent used in organic chemistry, wider range of substances

Examples Arrhenius Bronsted-Lowry Lewis HCl NaOH HClNH 3 :NH 3 BF 3 HCN The hydrogen ion in aqueous solution H + + H 2 O  H 3 O + (hydronium ion)

Dissociation of Strong Acids & Bases Strong acids & bases are assumed to dissociate (breakdown into ionic parts) completely in solution.

Dissociation of Weak Acids & Bases Weak acids & bases are assumed to dissociate only slightly (less than 5%) in solution. Act as molecules

Hydrochloric Acid (Strong) Hydrobromic Acid (Strong) HCl HBr Muriatic Acid - common name; Toilet bowl cleaners, masonry cleaners, gastric juice Carbonic Acid (Strong) H 2 CO 3 Carbonated water; club soda - soft drinks, blood buffer Sulfuric Acid (Strong) H 2 SO 4 Battery Acid; lead battery, air pollutant mist, acid rain Nitric Acid (Strong) HNO 3 Remove warts, causes yellow stains on skin Acetic Acid (Weak) HC 2 H 3 O 2 Vinegar; cooking, salads Phosphoric Acid (Weak) H 3 PO 4 Acidify soft drinks, in ATP and DNA Citric Acid (Weak) H3C6H8O6H3C6H8O6 Fruit juices Lactic Acid (Weak) HC 3 H 5 O 3 Builds up in muscles during exercise

Sodium Hydroxide (Strong) Barium Hydroxide (Strong) NaOH Ba(OH) 2 Lye, Caustic); make soap and textiles, oven cleaner, Drano, Liquid plumber Potassium Hydroxide (Strong) KOH make soap and textiles Magnesium Hydroxide (Strong) Mg(OH) 2 Milk of magnesia; laxative and antacid Calcium Hydroxide (Strong) Ca(OH) 2 Lime Water; astringent -causes contraction of skin pores Ammonium Hydroxide (Weak) NH 4 OH Ammonia in water; window cleaner, other cleaning solutions Ammonia (Weak) NH 3 Gas; inhalant to revive an unconscious person, anhydrous or liquid ammonia is injected into soil as a fertilizer Sodium Carbonate (Weak) Na 2 CO 3 Soda Ash; Detergents Sodium Phosphate (Weak) Na 3 PO 4 Sodium triphosphate; Detergents

HA Let’s examine the behavior of an acid, HA, in aqueous solution. What happens to the HA molecules in solution?

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

HA H+H+ A-A- Weak Acid Partial 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.

1. Acids that are made of only two elements (Binary) A. Prefix is always hydro B. Name the second element with the suffix -ic C. HCl = Hydrochloric Acid 2. Acids that are made of more than two elements; usually contain a polyatomic ion (Ternary) A. Polyatomic ions ending with –ate, you will change the suffix to -ic. example: H 2 SO 4 Sulfate Ion = Sulfuric Acid B. Polyatomics ending in –ite become –ous. For the acid containing the polyatomic with one less oxygen than the -ic, use the suffix -ous. example: H 2 SO 3 Sulfite Ion = Sulfurous Acid 2 Friends = ate-ic and ite-ous

1.Simply use the normal rules for naming compounds; ionic or covalent depending on the elements in the compound. 2.Most bases end with the polyatomic hydroxide ion –OH. example: NaOH = Sodium Hydroxide Mg(OH) 2 = Magnesium Hydroxide 3. For salts, use your oxidation table and follow normal ionic and covalent naming properties. example: KCl = Potassium Chloride

What is acid rain? CO 2 (g) + H 2 O  H 2 CO 3  H + + HCO 3 - Dissolved carbon dioxide lowers the pH Atmospheric pollutants from combustion NO, NO 2 + H 2 O …  HNO 3 SO 2, SO 3 + H 2 O …  H 2 SO 4 both strong acids pH < 5.3

pH of Rainwater across United States in 2001 Increasing acidity Why is the eastern US more acidic? air masses

When acids and bases with equal amounts of hydrogen ion H + and hydroxide ions OH - are mixed, the resulting solution is neutral. The resulting reaction will produce a salt precipitate and water NaOH (aq) + HCl(aq) NaCl + H 2 O base acid saltwater Ca(OH) HCl CaCl 2 + 2H 2 O base acid salt water

a. HBr + Ca(OH) 2 → b. Sulfuric acid combines with ammonium hydroxide c. Sodium Hydroxide plus Carbonic Acid

Strong Acid Added Weak Acid Added Summary List of Characteristics for Strong and Weak Acids and Bases Characteristic Strong Acid or Base Weak Acid or Base Moleculesfewlarge number Ionslarge number small number Conductivitystrongweak Bond Strengthweakstrong

The term pH was derived from the French word pouvoir hydrogene meaning “Hydrogen Power” pH is defined as the negative logarithm of the hydrogen ion concentration. The equation is: pH = - log [H+] similarly, pOH = - log [OH-] 1 x 10 -pH M

The pH scale, (0 - 14), is the full set of pH numbers which indicate the concentration of H+ and OH-ions in water. From 0 – 6 the substance is Acidic. 7 is neutral. From the substance is Basic. The lower the number the more acidic, the higher the number the more basic.

Litmus Three Common Indicators: Litmus (Vegetable dye) Paper: It is red below pH 4.5 and blue above pH 8.2. Phenolphthalein: indicator of acids (colorless) and bases (pink). Hydrion Paper: Ranges in color, Acids/Red, Bases/Blue

Acid/Base Definitions Arrhenius Model Acids produce hydrogen ions in aqueous solutions Bases produce hydroxide ions in aqueous solutions Bronsted-Lowry Model Acids are proton (H + ) donors when added to water Bases are proton (H + ) acceptors when added to water Lewis Acid Model Acids are electron pair acceptors Bases are electron pair donors

Bronsted-Lowry Acids Acids are hydrogen ion (H +) donors Bases are hydrogen ion (H + ) acceptors HCl + H 2 O H 3 O + + Cl - donor acceptor HCl is the acid because it donated a Hydrogen ion and water is the base by accepting the Hydrogen ion.

Acid Rain Unpolluted rain has a pH of 5.6 Rain with a pH below 5.6 is “acid rain“ CO 2 in the air forms carbonic acid CO 2 + H 2 O H 2 CO 3 Adds to H + of rain H 2 CO 3 H + (aq) + HCO 3 -(aq) Formation of acid rain: 1. Emission of sulfur and nitrogen oxides from the burning of fuels expecially coal with high S content, power stations, oil refineries, vehicles as well as bacterial decomposition, and lighting hitting N 2 SO 2 26 million tons in 1980 NO and NO 2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO 2 2. Reactions in the atmosphere form SO 3 2SO 2 + O 2  2 SO 3 3. Reactions with atmosphere water form acids SO 3 + H 2 O  H 2 SO 4 sulfuric acid NO + H 2 O  HNO 2 nitrous acid HNO 2 + H 2 O  HNO 3 nitric acid 4. Effects of Acid Rain Decline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rain Extensive fish kills in spring from runoff due to accumulation of large amounts of acid on the snow Dissolves minerals Mg, Ca, and K from the soil and waxy coatings that protect leaves from bacteria Corrodes metals, textiles, paper and leather