Acids and Bases
Naming Acids
• Binary Acids- Contains H and one other element
• Use the prefix hydro- and the root of the second
element (change end to “ic”) + acid
• Examples:
•
HCl- hydrochloric acid HF- hydrofluoric acid
•
HI- hydroiodic acid
HBr- hydrobromic acid
• *Special case- for acids w/ 3 elements (polyatomic
ions), but no O:
•
Prefix hydro- and the root of the polyatomic ion
(change end to “ic”) + acid
•
HCN
hydrocyanic acid
Naming acids, cont.
• Oxyacids- Contains an H and a
polyatomic ion with an Oxygen
– Use the root of the ion, add a suffix (ic or
ous), then acid
• **Do not use the prefix “hydro” for these!
• When to use ic or ous:
– If the ion ends in “ate” = change end to “ic”
• Ex: HNO3 (anion = nitrate) = nitric acid
– If the ion ends in “ite” = change end to “ous”
• Ex: HNO2 (anion = nitrite) = nitrous acid
Naming Bases
• Name of element + hydroxide
•
Mg(OH)2 magnesium hydroxide
•
KOH potassium hydroxide
• **H must be at the beginning of the
formula to be an acid**
What is an acid?
-- Sour taste
-- Turns blue litmus paper
pink
-- Makes a conjugate base
-- Reacts with some metals to
make H2 gas
-- pH less than 7
-- More H+ ions than OH-- Conducts electricity
-- Usually dissolved/diluted in
H2O
-- H+ ion donor in reactions
-- Donates an H+ to base
-- Sometimes water acts as the
acid in the reaction
What is an acid?
Strong Acids
Weak Acids
•Sulfuric Acid – H2SO4
•Hydrofluoric Acid – HF
•Hydrobromic Acid – HBr
•Acetic Acid – HC2H3O2
•Hydrochloric Acid – HCl
•Hydrosulfuric Acid – H2S
•Nitric Acid – HNO3
•Carbonic Acid – H2CO3
•Ionize completely in reactions
•Ionize partially in reactions
•Reaction goes to completion
(cannot go in reverse)
•Reaction in equilibrium (can
go in reverse)
•Good conductors of electricity
•Does not conduct electricity
well
•Make weak conjugate bases
•Make strong conjugate bases
What is a base?
-- Bitter taste
-- Slippery to touch
-- Turns pink litmus
paper blue
-- More OH- ions than H+
ions
-- pH greater than 7
-- Makes conjugate acid
in reactions
-- Accepts H+ from acid
-- Conducts electricity
-- Usually
dissolved/diluted in H2O
-- Sometimes water acts
as a base in reactions
What is a base?
Strong Bases
Weak Bases
•Litihium hydroxide – LiOH
•Ammonia – NH3
•Sodium hydroxide – NaOH
•Aluminum hydroxide – Al(OH)3
•Potassium hydroxide – KOH
•Iron (III) hydroxide – Fe(OH)3
•Magnesium hydroxide – Mg(OH)2
•Dissociate (dissolve) completely
in water solutions to make metal
ions and OH ions
•NaOH  Na+ + OH•Make weak conjugate acids
•Partially dissociates in water
solutions to make conjugate base
and OH ions
•CH3NH2 + H2O ↔ CH3NH3+ + OH•Make strong conjugate acids
What are conjugate acids and bases?
-- Conjugate acid -- created when a base accepts an H+
-- Conjugate base – created when an acid donates (gives away) an H+
-- Creates a conjugate acid-base pair – 2 substances related to each
other by donating/accepting H+ ions in a reaction
-- General equation for a acid-base reaction is:
HX
ACID
+
H2O
BASE

H3O+ +
C. ACID
XC. BASE
So, H2O and OH- are a conjugate acid-base pair and NH3 and NH4+ are
a pair as well.
EXAMPLES: Identify the acid/base/c. acid/c. base
NH3 + H2O  NH4+ + OHNH3 + H2O ↔ NH4+ + OHHCN + H2O ↔ H3O+ + OH-
Other things to know…
-- Water is amphoteric, which means it can act as an
acid or a base. It depends on what it reacts with that
decides if it’s an acid or a base.
-- Monoprotic acids – only donate 1 H+ to the reaction
-- i.e. NH4 will become NH3 H2O will become OH-- Diprotic acids – donate 2 H+ to the reaction
-- i.e. H2SO4 will become SO42- H2CO3 will become
CO32-- Polyprotic acids – donate 3 or more H+ to the reaction
-- i.e. H3PO4 will become PO43-- The process of giving off H+ ions is called ionization
-- The model we use to identify acids/bases/c. acids/c.
bases is called the BrØnsted-Lowry model of acids
and bases
What is the pH scale?
-- The pH scale measures how acidic or basic a substance is.
-- pH greater than 7 is basic
-- pH less than 7 is acidic
Oven cleaner
Hair remover
Household
ammonia
Milk of magnesia
Soap/Detergent
Antacid
Blood
Pure water
Milk
Coffee
Tomatoes
Soft drinks
Stomach
acid
Battery acid
pH (power of hydrogen)
•Acids, Alkalis and Neutralization
How do you calculate pH?
FORMULA:
pH = -log [H+]
Example 1: What is the pH of a solution with a [H+] of 1x10-2?
pH = - log (1x10-2)
= - (log 1 + log 10-2)
= - [0 + (-2)]
= - [-2]
= 2
Example 2: What is the pH of a neutral solution?
pH = - log (1x10-7)
= - (log 1 + log 10-7)
= - [0 + (-7)]
= - [-7]
= 7
How do you calculate pOH?
-- pOH is the concentration of the OH- ions in a solution
-- pH + pOH = 14
pOH = -log [OH-]
FORMULA:
Example 1: Ammonia has an [OH-] concentration of 4.0x10-3.
Calculate pOH and pH.
pOH = - log (4x10-3)
= - (log 4 + log 10-3)
= -[0.60 + (-3)]
= - (-2.40)
= 2.40
pH + 2.40 = 14
pH = 14-2.40
= 11.60
Acid Base Indicators
-- Chemical dyes that change colors depending on their placement in an
acidic or basic solution.
-- Some indicators may remain colorless in certain pH ranges.
-- Used in toys that change colors when water is added.
Indicators
Neutralization
• Is a chemical
reaction between
and acid and a
base in an
aqueous solution
• Usually a double
replacement
reaction
• Makes water and a
salt
Neutralization Reactions
-- Reaction where an acid and base react in an aqueous solution to
produce a salt and water
EXAMPLE: Mg(OH)2
+ 2HCl
base

MgCl2
acid
+
2H2O
salt
water
MgCl2 made up by: Mg2+ from base and Cl- from acid
More Examples:
1.
Write the salt and water formed from HCl reacting with NaOH.
HCl
+
NaOH

NaCl
+
salt
2.
H 2O
water
Write the equation and identify the acid, base, salt, and water formed
when nitric acid reacts with cesium hydroxide.
HNO3
acid
+
CsOH
base

CsNO3 +
salt
H2O
water
More Practice…..
• 1) hydrobromic acid and calcium hydroxide
• 2) sulfuric acid and potassium hydroxide
• 3) acetic acid and ammonium hydroxide
Answers
• 1) 2HBr + Ca(OH)2  CaBr2 +
H2O
• 2) H2SO4 + 2KOH  K2SO4 +
H2O
• 3) HCH3COO + NH4OH 
NH4CH3COO + H2O
Label as Acid, Base, or
Salt
•
•
•
•
•
•
•
A) Na2SO4
B) Mg(OH)2
C) Ba3(PO)4
D) H3PO4
E) HI
F) Cu(OH)2
G) CsCl