Part 16 - Acid-Base Theories

Arrhenius

• yields H+ or H₃O - acid

• yields OH- - base

• water ion theory of acids

Bronsted- Lowry

• proton donor - acid

• proton acceptor - base

• protonic concept of acidity

Lewis

• electron acceptor - acid

• electron donor - base

Svante August Arrhenius

• Swedish scientist

• created the acid-base theory that states that acids yield H+ or H₃O and bases yield OH-

hydronium (H₃O)

forms when hydrogen ion / proton (H+) binds to a water molecule (H2O)

strong acid

acid that dissociates completely

weak acid

acid that doesn’t dissociate completely

• HCl

• HNO₃

• HSO4

strong Arrhenius acids (3)

HF

weak Arrhenius acid

conjugate acid / base

forms when acid or base gains or lose a single H+ ion

amphoteric

Water is _____ and plays the role of a base or acid

conjugate acid

formed when a base gains a H+

conjugate base

forms when an acid loses a H+

• NaOH

• KOH

• Ca(OH)2

• LiOH

Arrhenius bases (4)

electrophile

Lewis acids are also known as ____

nucleophile

Lewis base are also known as ____

coordinate covalent bonding (dative bond)

bond where both share electrons come from the same atom

standard covalent bond

bond where each atom gives one electron to the shared pair

strong electrolytes

strong acids and bases indicate _____

weak electrolytes

weak acids and bases indicate _____

• acetic acid (CH₃COOH)

• ammonium (NH₄)

weak acids (2)

• ammonia

• sodium bicarbonate (NaHCO₃)

• aluminum hydroxide ( Al(OH)_{3 )}

weak bases (3)

• hydrochloric acid (HCl)

• hydrobromic acid (HBr)

• nitric acid (HNO₃)

• hydroiodic acid (HClO₄)

• sulfuric acid

strong acids (5)

Pearson’s Hard Soft Acid Base Theory

this theory’s principle is that hard acid prefer to bind with hard bases. Soft acids prefer to bind with soft bases

hard acid

• small ionic radius

• has positive charge

• empty orbital in valance shell

• does not easily get excited outer electrons

• alkaline, alkaline earth, lighter transition metals in high oxidation states

• H

• Na

• Li

• Mg

• Ba

• Ti₄+

• Fe₃+

hard acids (7)

soft acid

• large ionic radius

• low positive charge

• filled atomic orbitals

• has easily excited outer electrons

• heavy transition metals in lower oxidation state

• Cu+

• Hg+

• Ag+

soft acids (3)

hard base

• small ionic radius

• high electronegativity

• low polarizability

• hard to oxidized

• have empty orbitals of high energy

• F-

• Cl-

• OH-

hard base (3)

soft base

• large ionic radius

• low electronegativity

• high polarizibility

• easily oxidized

• have empty low-lying orbitals

a) strong acid gives rise to a weak conjugate base

according to the Bronsted-Lowry theory, which of the following is true?

a) strong acid gives rise to weak conjugate base

b) anions, cations, and molecules may show acidic or basic behavior

c) acids and bases react to form salts

d) none