Acids, Bases and pH
Oh My!
Acids
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produce H+ ions in aqueous solutions
are proton donors
are electron pair acceptors
the word “acid” comes from the Latin
acere, which means 'sour'
taste sour
acids change litmus (a blue vegetable
dye) from blue to red
their aqueous (water) solutions conduct
electric current (are electrolytes)
react with bases to form salts and water
evolve hydrogen gas (H2) upon reaction
with an active metal (such as alkali
metals, alkaline earth metals, zinc,
aluminum)
Bases
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produce OH- ions in aqueous solutions
are proton acceptors
are electron pair donors
taste bitter (don't taste them!)
feel slippery or soapy (don't arbitrarily
touch them!)
bases don't change the color of litmus;
they can turn red (acidified) litmus back
to blue
their aqueous (water) solutions conduct
and electric current (are electrolytes)
react with acids to form salts and water
Examples
Examples
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citric acid (from certain fruits and
veggies, notably citrus fruits)
ascorbic acid (vitamin C, as from certain
fruits)
vinegar (5% acetic acid)
carbonic acid (for carbonation of soft
drinks)
lactic acid (in buttermilk)
Indicators:
pH:
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detergents
soap
lye (NaOH)
household ammonia
Substances that detect the presence of acids or bases. Each substance turns a
color based upon what it is detecting.
Stands for the “power of Hydrogen.” It represents the measure of the concentration of
hydrogen ions in a solution, which is a measure of acidity or alkalinity. The pH scale runs
from 0 to 14, and each number indicates a ten-fold increase. Seven is pH neutral;
numbers below 7 indicate increasing acidity, with 1 being most acid. Numbers above 7
indicate increasing alkalinity, with 14 being most alkaline.