Properties of Acids,
Bases and Neutrals
Taste: Have you ever taken a bite
out of a sour lemon? When you taste something sour, your face kind of looks like
this - *. Lemon juice is an acid and acids can taste sour. Baking soda has a
bitter taste that most people don't like - *. It is an example of a base and
bases can taste bitter. Water is not an acid or a base, it is neutral and has
no particular taste. Please don't ever taste strong acids or strong bases or
any other chemicals that are not food!
Feel: What happens if you're slicing lemons and some juice
get into a cut on your finger? YOW! It stings. Acids sting cuts.
If you've ever spilled bleach or soap on the floor, you may have
noticed that it is slippery. Bases such as bleach and soap are slippery.
Our neutral substance, water, would be a good choice for cleaning
up acids and bases because it doesn't sting and it's not slippery.
Please don't ever touch strong acids or strong bases because they
can be harmful to your skin and may damage sensitive tissues such
as your eyes.
Examples of acids, bases and neutrals
What are some common acids, bases and neutrals? These are some acids you may
be familiar with: lemon juice, vinegar, orange juice, carbonated beverages, stomach
acid and battery acid. Do the food items on the list taste and feel like acids?
These are some bases you may have seen: baking soda, bleach, ammonia, drain cleaner
and soap. Some neutrals are: water, milk and hand lotion.
You may be wondering what acids and bases do to other chemicals. Acids dissolve
metals - tomato sauce in an aluminum pan, break up proteins - marinating meat,
conduct electricity - battery acid and dissolve carbonate compounds - bacterial
acid making cavities on teeth. Bases and acids neutralize each other. Mixing
equal amounts of similar strength acids and bases produces a neutral substance
Measuring Acids and Bases
You have probably been told not to taste or touch strong acids and bases. So
how do we know how strong these chemicals are? The pH scale is a tool for measuring
acids and bases. It is an expanding scale that goes from 0-14. The lower the
number the more acidic the substance, a pH of 7 right in the middle is neutral
and the higher the number the more basic the substance. The color of the pH paper
matches up with the numbers on the pH scale to tell you what kind of substance
you are testing.
The Power of Hydrogen
The abbreviation pH stands for Ůthe power of hydrogenÓ because
it is actually a measure of the number of hydrogen ions or protons
in a solution (pH = -log[H+]
or pH of 7 in water means there are 10-7 moles of H+ ions per liter). Acids
release hydrogen ions ( positively charged particles) from solution
and bases remove
hydrogen ions from solution. Because the pH scale is logarithmic, this means
a substance of pH 5 is 10 times more acidic than a substance of pH 6.