Acids Bases

react with metals

to form H2 gas

vinegar, milk,

soda, apples,

citrus fruits

bitter taste

turn litmus blue

substance that changes color in an acid or base

Examples: litmus - red/blue phenolphthalein - colorless/pink goldenrod - yellow/red red cabbage juice - pink/green

•Acids contain hydrogen ions

•Bases contain hydroxide ions (OH-)

Savante Arrhenius, Swedish

chemist who by 1890

formulated the first useful

theory for acids.

•Acids are proton (H+) donors.

•Bases are proton (H+) acceptors.

• Conjugate acid-base pairs are formed.

HCl + H2O Cl

– + H

3O

+

conjugate acid conjugate base

base acid

Pairs identifies the particles formed when H+ ions

are donated and accepted when an acid or a base is

dissolved in water.

Base gains H+ conjugate acid formed

Particle that remains conjugate base

HCN(aq) + SO4−2

(aq) → HSO4−

(aq) + CN−(aq)

H2O(l) + NH3(aq) → NH4+

(aq) + OH−(aq)

HCO3−

(aq) + H2O(l) → H3O+(aq) + CO3

−2(aq)

HCO3−

(aq) + H2O(l) → H2CO3(aq) + OH−(aq)

Dissociation: ionic compounds dissolve to produce ions

Ionization: molecular compounds dissolve in water to produce ions

The level of dissociation/ionization determines the strength of acid/base.

Strong Acid/Base 100% ionized in water many ions produced strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

Weak Acid/Base

• does not ionize completely

• few ions produced

• weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Acids & Bases

Basis for pH scale that is used to quantitatively examine the H+ ion concentration of solutions.

Kw= [H+][OH-]

Kw = (1.0 x 10-7M) x (1.0 x 10-7)

Kw =1.0 x 10-14

pH scale is derived from the value of Kw

pH of Common Substances

0

7

NEUTRAL INCREASING

BASICITY

14

INCREASING

ACIDITY

pH = -log[H3O+]

pOH = -log[OH-]

pH + pOH = 14

What is the pH of 0.050 M HNO3?

pH = -log[H3O+]

pH = -log[0.050]

pH = 1.3

Acidic or basic? Acidic

Acids & Bases

Analytical method in which a standard solution is used to determine the concentration of an unknown solution.

standard solution

unknown solution

Equivalence point (endpoint)

Point at which equal amounts of H3O+ and OH- have been added.

Determined by…

indicator color change

• dramatic change in pH

moles H3O+ = moles OH-

MV n = MV n

M: Molarity

V: volume

n: # of H+ ions in the acid or OH- ions in the base

42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4.

H3O+

M = ?

V = 50.0 mL

n = 2

OH-

M = 1.3M

V = 42.5 mL

n = 1

MV# = MV#

M(50.0mL)(2)

=(1.3M)(42.5mL)(1)

M = 0.55M H2SO4

Chemical reaction between an acid and a base.

Products are a salt (ionic compound) and water.

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

• Salts can be neutral, acidic, or basic.

• Neutralization does not mean pH = 7.

Double replacement reaction where a precipitate is formed due to the insolubility of the compound that is formed.

Refer to the solubility rules.

A chemical reaction in which one reactant loses electrons and another gains electrons.

The reactant being oxidized (losing electrons) is said to be the reducing agent.

The reactant that is reduced (gaining electrons) is said to be the oxidizing agent.

2Fe + O2 2FeO

All batteries produce electricity by means of redox reactions.