C16 - Acid-Base Equilibrium (Gen. Chem 1)

Arrhenius definition

changes in H⁺ & OH^- concentration

Bronsted-Lowry definition

donation & accepting protons

Lewis definition

donating & accepting electron pairs

conjugate acid/base

the new acid/base formed after reaction

relative CA/CB strengths

• strong acid = weak CB

• strong base = weak CA

autoionization of water

K_c(w) = [H₃O⁺][OH^-]

ion-product constant

K_w = [H⁺][OH^-] = 1 × 10^-14

pH & pOH

pH = -log[H⁺]

pH + pOH = 14.00

K_c (acid-base dissociation)

K_c = [H⁺][A^-]/[HA]

• for weak acids/bases

% ionization

[ionized]/[initial] • 100

amphoteric

substances which can act as an acid or a base

polyprotic

substances which can donate/accept multiple H⁺ ions

acid-base salt solutions

cations: donate protons

anions: accept protons

• only cation → acidic

• only anion → basic

• neither → neutral

• both → depends on relative strengths

A-B strength gfactors

• polarity

• bond weakness

• stable conjugate

binary acids

a hydrogen and a nonmetal element (acid)

• acidity increases with electronegativity & size (right & down the table)

oxyacids

OH & other oxygen groups bound to a central atom, resulting in an acid

• acidity increases as the OH connector becomes more electronegative