ACIDS & BASES

Acid Nomenclature Flowchart Oxyacids or Ternary -ite -ate Binary -ide

NAMES AND FORMULAS A Review HX means Acid If anion ends in “–ide” Acid name begins with “hydro-” Ends with “–ic” , followed by “Acid” HCl – Hydrochloric Acid (Chloride) HBr – Hydrobromic Acid (Bromide) HCN – Hydrocyanic Acid (Cyanide)

NAMES AND FORMULAS If anion ends in “–ite” Acid ends with “–ous”, followed by “Acid” H2SO3 – Sulfurous Acid HNO2 – Nitrous Acid H3PO3 – Phosphorous Acid

NAMES AND FORMULAS If anion ends in “–ate” Acid ends with “–ic” ,followed by “Acid” H2SO4 – Sulfuric Acid HNO3 – Nitric Acid H3PO4 – Phosphoric Acid

NAMES AND FORMULAS Bases named same as ionic compound NaOH –Sodium Hydroxide (Lye) Ca(OH)2 – Calcium Hydroxide (Lime) Pb(OH)2 – Lead Hydroxide KOH – Potassium Hydroxide

WATER IONIZATION Water molecules in continuous random motion Collisions between two molecules Result in transfer of hydrogen ion H2O + H2O H3O+ + OH- H3O+ = hydronium ion OH- = hydroxide ion

3 Theories Acid-Base Theories

3 Theories Acid/Base Theory #1: Arrhenius (traditional) a) Acids – produce H+ ions (or hydronium ions H3O+) in aqueous solution i: Monoprotic Acid  gives up 1 H+ (HCL) ii: Diprotic Acid  gives up 2 H+ (H2SO4) iii: Triprotic Acid  gives up 3 H+ (H3PO4) b) Bases – produces OH- ions in aqueous solutions

Arrhenius acid is a substance that produces H+ (H3O+) in water Arrhenius base is a substance that produces OH- in water

Brønsted – Lowry Theory #2: Brønsted – Lowry a) Acids – proton (H+) donor (H+ is given away) b) Bases – proton (H+) acceptor (H+ gained) A “proton” is really just a hydrogen atom that has lost it’s electron!

A Brønsted-Lowry acid is a proton donor A Brønsted-Lowry base is a proton acceptor conjugate acid conjugate base base acid

Lewis a) Lewis acid – electron pair acceptor Theory #3 – Lewis a) Lewis acid – electron pair acceptor b) Lewis base – electron pair donor

WATER DISSOCIATION, SIMPLIFIED Dissociation of water: H2O  H+ + OH- One H+ and one OH- produced, so [H+] = [OH-] [ X ] = concentration (Molarity)

PROPERTIES OF ACIDS Sour or tart taste in foods Strong Acid = Strong Electrolyte Release H+ ions in water Turn blue litmus paper Red

Hydrogen Ion in Water Water + a proton  Hydronium Ion H2O + H+  H3O +1 The H+ ion has no electrons so it attached itself to a water molecule to share its electrons

ARRHENEIUS ACIDS Theory developed by Arrhenius (1859-1927) Defined acids and bases as compounds that ionize to produce H+ and OH-

ARRHENIUS ACIDS Theory: substance that contains hydrogen, and releases the H+ in water HCl + H2O  (1) H3O+ (aq) + Cl - (aq) monoprotic   H2SO4 + H2O  (2) H3O+ (aq) + SO4-2 (aq) diprotic H3PO4 + H2O - (3) H3O+ (aq) + PO4-3 (aq) triprotic

Types of Arrhenius Acids Monoprotic acids contain 1 ionizable proton HCl, HBr, HF, HI Diprotic acids contain 2 ionizable protons H2SO4 Triprotic acids contain 3 ionizable protons H3PO4

PROPERTIES OF BASES Feels slippery Bitter taste Strong Base = Strong Electrolyte Produce hydroxide ions in water Red litmus turns Blue in a Base (RBB) EX: LYE USED IN SOAPMAKING AMMONIA USED IN CLEANING

ARRHENIUS BASES Substance that contains OH and releases the OH- in water. NaOH + H2O  Na+1 (aq) + OH- (aq) Mg(OH)2 + H2O  Mg +2 (aq) + 2 OH- (aq)

Some Definitions Arrhenius acids and bases Acid: Substance that, when dissolved in water, increases the concentration of hydrogen ions (protons, H+). Base: Substance that, when dissolved in water, increases the concentration of hydroxide ions.

Complete book practice problems Pg 609 #34,43,44,45,46 Or check your Power packet ( Acids + Bases) pg 9

Three definitions of acid Who Theory: Acid= When Arrhenius increases H+ 1880’s Brønsted & Lowry proton donor 1923 Lewis Electron-pair acceptor

ALTERNATE THEORIES Not all materials with acidic/basic properties in aqueous solution contain H or OH. Don’t fit Arrhenius definition of acids & base Johannes Brønsted (1879-1947) and Thomas Lowry (1874-1936) independently proposed a new definition.

Some Definitions Brønsted–Lowry: must have both 1. an Acid: Proton donor and 2. a Base: Proton acceptor

Brønsted – Lowry Acids and Bases B/L Acid is a hydrogen ion donor B/L base is a hydrogen ion acceptor Arrhenius acids and bases fit into the Brønsted – Lowry Theory

Brønsted-Lowry acids and bases are always paired. The Brønsted-Lowry acid donates a proton, while the Brønsted-Lowry base accepts it. Which is the acid and which is the base in each of these rxns?

Brønsted – Lowry Acids and Bases NH3 + H2O g NH4+ + OH- Ammonia is a base accepts hydrogen ion Water is an acid donates hydrogen ion

What Happens When an Acid Dissolves in Water? Water acts as a Brønsted–Lowry base and abstracts a proton (H+) from the acid. As a result, the conjugate base of the acid and a hydronium ion are formed. Movies…

A Brønsted–Lowry acid… …must have a removable (acidic) proton. HCl, H2O, H2SO4 A Brønsted–Lowry base… …must have a pair of nonbonding electrons. NH3, H2O

Conjugate Acids and Bases: From the Latin word conjugare, meaning “to join together.” Reactions between acids and bases always yield their conjugate bases and acids.

Brønsted – Lowry Acids and Bases Conjugate Acid Formed when a base gains a hydrogen ion. NH4+ is the Conjugate Acid Conjugate Base What remains when an acid has donated the hydrogen ion. OH- is the Conjugate Base

Brønsted – Lowry Acids and Bases Conjugate Acid Conjugate Base Base Acid

Brønsted – Lowry Acids and Bases Conjugate acid / base pair Two substances that are related by the loss or gain of a hydrogen ion. HCl + H2O g H3O+ + Cl- Water is Amphoteric - Acts as both Acid and Base

Brønsted – Lowry Acids and Bases In General: Conjugate Base of a Strong Acid is weak HCl (acid) has a weak conjugate base in Cl- Conjugate Acid of a Strong Base is weak NaOH (base) has a weak conjugate acid in Na+

Remember the Lewis Dot Structure? ALTERNATE THEORIES Gilbert Lewis (1875-1946) focused on the donation or acceptance of electrons. Lewis acid accepts electrons to form a covalent bond Lewis base donates electrons to form a covalent bond Remember the Lewis Dot Structure? This is the same guy…

Acid-Base Definitions Type Acid Base Arrhenius H+ producer OH- producer Brønsted-Lowry H+ donor H+ acceptor Lewis Electron-pair acceptor Electron-pair donor