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Acids and Bases
What are acids and bases?
Common acid
Vinegar
Tastes sour
Common acid
Baking soda
Tastes bitter
There are many kinds of acids and bases. Some strong, some weak,
some can burn through your hands, some you can eat. So, what are
acids and bases. The simple explanation is that an acid is a proton
seller and a base is a proton eater.
Proton for
sale !
A
Acid
I want to eat
a proton !
B
Base
I really want to
eat a proton
B
Strong base
Nah, I don’t feel
hungry.
B
Weak base
I really want to
sell this proton !
+
+
I can sell it later.
A
+
A
+
Strong acid
Weak acid
Here are a few acids and bases
Acids, strongest to weakest
Bases, weakest to strongest
Sulfuric (H2SO4)
Hydrochloric (HCl)
Phosphoric (H3PO4)
Acetic (vinegar)
Carbonic (H2CO3)
Acetate (CH3CO2-)
Bicarbonate (baking soda)
Ammonia (NH3)
Carbonate (CO3-)
Hydroxide (OH-)
pH (Power of Hydrogen)
There are strong acids and bases , and there
are weak ones. But how do you measure
acidity? Chemists use pH to measure it. pH
ranges from 0 to 14. Water has a pH of 7, which
is neutral. The lower the pH, the more acidic the
solution is. The higher the pH, the more basic
the solution is.
Some acids and bases with their pH
0
1
2
3
4
5
6
7
Acids
5% sulfuric acid
stomach acid
lemons, vinegar
apples, grapefruit, oranges,
Coca-Cola
tomatoes
coffee, bread, potatoes,
natural rivers
pure water
Bases
pure water
sea water, baking soda
7
8
9
10 water in Mono Lake, milk of
magnesia
11
12 lime water
14 lye, 4% sodium hydroxide
You can see that since 5% sulfuric acid has a pH of 0, highly
concentrated sulfuric acid would have negative pH.
Measuring pH
Some dyes will show different colors under
different pH values. The pH papers have
dyes that show different colors in different
pH values but most have a range. For
example, take the picture right here. The
range of this type it is 1 to 12. If the paper
turns red, the pH would be 1, a strong acid.
If the paper turns purple, the pH would be
12, a strong base. If the paper turns green,
the pH would be 8, a weak base.
.
When acids and bases meet
When a acid and base of equal strength
meet, the acid gives of it’s proton and the
base “eats it up.” With the acid’s proton and
the base’s “hunger” gone, the solution
becomes neutral. For example, when you
mix HCl (hydrochloric acid) with NaOH
(sodium hydroxide), the H, along with the
OH, becomes water and the Na plus the Cl
become NaCl (a.k.a. table salt) so the whole
solution turns neutral.
Here!
Thanks!
+
Some common acid –base reactions
There are many common acid –base reactions like when you rise bread. In
baking powder there is sodium bicarbonate (baking soda) and an acid.
When the baking powder is mixed with water and flour, the reaction
between the acid and base will release carbon dioxide. When heated, the
carbon dioxide expands, causing the bread rise. Coco-Cola uses a similar
reaction.
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