Objective ChecklistAt the end of this lesson, will be able to:
Identify and classify acids and bases based on their properties
Name acids and bases
Acids and BasesImportant Control digestion in our bodies (stomach acid
and activation and deactivation of enzymes)Found in foods and used in industry
Acid or a Base?Taste:
Acids- sour (ex. Lemons- citric acid)Bases- bitter (ex. Soap)
Touch:Bases- slippery to the touch and corrosive to the
skin What does corrosive mean?
Acids- not slippery and corrosive to the skinReaction with Metal:
Acids- react; forms H2 gas (bubble formation)Bases- don’t react
Using pHWhat is pH used for?What does the scale look like?What substance is considered neutral?Where do the following substances place on
the scale?Acid rain, normal rain, lemon juice, stomach
juicesBaking soda, human blood, oven cleaner,
window cleaner (ammonia)
ConductivityBoth acids and bases have or form ions in
solutionIn solution, these ions can conduct electricity,
so they are electrolytesCan you think of any everyday items that
contain an acid or a base (alkali) to conduct electricity?
IndicatorsTo determine pH and whether something is
an acid or base, we use indicatorsIndicators change color depending on pHLitmus paper is created through extracting
the chemical from lichens Acid: blue litmus paper turns red (BRA)Base: red litmus paper turns blue (RBB)Neutral: paper stays same color
ACID RED BASE BLUE
DemonstrationWhat color should the acid (lemon juice,
citric acid) turn the blue litmus paper? Red litmus paper?
What color should the base (bleach) turn the red litmus paper? Blue litmus paper?
How do we test whether the unknown is an acid or base? If blue litmus stays blue, can we conclude that it is a base? Why or why not?
Recognizing AcidsIn acids, the formula often has a “H”
(hydrogen ion – may be more than one) on the left side of the formula (ex. HCl)Can also appear on the right side as “-COOH”
(organic acid group) (ex. CH3COOH) They are bonded to an anion (one or more
non-metals)
To identify acids from formulas, look for “H” on the left or “-COOH” on the right
Recognizing AcidsWhich of the following are acids?
HBr(aq) NaCl(aq)H2SO4(aq) HCOOH(l)
NaOH(aq) H2O(l) HNO3(aq)C6H5COOH(l)
K2SO4(aq)
Naming AcidsIUPAC method: name as an aqueous ionic
compound What would HCl be using these rules?
Another method:1) When containing hydrogen and non-metallic
element (anion name ends in –ide):Use prefix “hydro” and suffix “ic”Ex. HCl becomes hydrochloric acid
What would HF be using this rule?
Naming Acids cont…2) When acid contains oxygen (ex. H2SO4(aq)),
name based on the anion What is the anion in H2SO4(aq)?
If anion ends in “ate”, name of acid ends in “ic”
Ex. H2SO4(aq) contains sulfate anion (SO42-) and is then named sulfuric acid
What is the acid name of H3PO4(aq)? How do we approach naming it?
Naming Acids cont…3) if anion ends in “ite”, name of acid ends
in “ous”H2SO3 (aq)contains the anion sulfite (SO3
2-), so the acid is named sulfurous acid
What is the name of the acid HNO2(aq)?
PracticeAcid Formula Name
HNO3(aq)
chromic acid
HI(aq)
hydrobromic acid
HClO(aq)
nitric acid
H2CrO4(aq)
hydroiodic acid
HBr(aq)
hypochlorous acid
Recognizing BasesOften, bases are identified by presence of
“OH-” (hydroxide ion) with a metal ion or the ammonium ion (NH4
+)It is more complicated than this, but for now:
Any compound with high solubility and an OH on right is a base
Name base as would name an ionic compound What would NaOH be named using rules we
already know?
PracticeBase Name
KOH(s)
ammonium hydroxide
calcium hydroxide
Mg(OH)2(s)
aluminium hydroxide
potassium hydroxide
NH4OH(aq)
magnesium hydroxide
Al(OH)3(s)
Ca(OH)2
NeutralizationReaction between acid and a base which
produces water and a saltThe acidic and basic properties disappearWhy would this be important? Give an
exampleEx. A bee’s sting contains methanoic acid
which dissolves nerve endings in the skin (lots of pain!). Sting creams containing ammonia limit the pain as the ammonia neutralizes the acid
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