The opposite of an acid is a base. A base has a pH higher than 7. pH is the number of Hydrogen ions (an ion is a charged atom, it has an extra electron or one electron fewer) that come off of a chemical when it is dissolved in water. Bases give off Hydroxide (OH-) ions. Some common bases around your house are bleach, wood ashes, baking soda, toilet bowl cleaner, soap, and wasp stings. Some of these bases are very strong, like toilet bowl cleaner and are therefore dangerous, but others are fairly mild, like baking soda and can be eaten.
Testing For Bases
Test for the presence of a base by dipping the end of a pH testing paper into the liquid chemical. Be careful to not mix the chemicals with one another during your testing; when some of these chemicals are mixed they can produce hazardous fumes. Wear gloves and goggles.
- Wear gloves and goggles.
- If your chemical is dry mix it with distilled water first. Use approximately 2 T. water to 1/4 t. chemical (exact amounts do not matter).
- Dip the end of a pH test paper briefly into the liquid chemical you wish to test. Then lay the paper out on the counter. (After the papers have dried you can paste them into a science notebook and label them with the chemical names and their approximate pH.)
- Check the color the pH paper turns against the chart that came with the pH papers.
- Arrange your chemicals in order from most acidic to neutral to most basic.
- Dispose of the chemicals by flushing down the sink with plenty of water. Rinse your containers and measuring devices thoroughly. Throw away gloves that were used.
Some things to test:
- toilet bowl cleaner
- window cleaner
- baking soda (mixed in with water)
- cleanser, like Ajax (mixed with water)
- fruit juice
- laundry soap
- pickling lime
- think of other stuff you have around
Many cleaners are basic, because they combine with grease to make soap and they also neutralize acids, many of which are in the messes we make.
We tested Sodium Hydroxide (drain cleaner), Sodium Bicarbonate (baking soda), and Calcium Hydroxide (pickling lime). You can turn your householdy chemicals into a real chemistry set like ours with our free printable chemical labels.
In the Laundry
The laundry is a great place to experiment with the effects of acids and bases and the chemicals we use to clean them. (Plus you’ll get some laundry done).
Have the kids treat some stains with different chemicals to see what gets the stain out. Try laundry soap, vinegar, borax, enzyme spot treater, lemons, bleach, and ammonia. Don’t use them all at once, but one at a time, though any of these can be safely used with regular laundry detergent. In particular do not mix bleach with other cleaners as it can create deadly fumes.
Some acidic stains which should be treated with basic treatments (the kids can find the basic chemicals using the pH testing paper):
- coffee, tea
- soft drinks
- children’s medicine
- fruit, fruit juice
- old perspiration stains (which have oxidized)
- antiperspirant stains (they call it pH balanced because the antiperspirant, an acid, neutralizes the basic perspiration of the human body)
- old urine stains
Some basic stains which should be treated with an acidic cleaner:
- fresh perspiration stains
- fresh urine stains
Try soaking in vinegar before laundering
Why would a base be used to clean an acid and vice versa?
OH- + H+ ——> H2O
If you combine the hydroxide ions with the hydrogen ions you get water, that is neutralization.
- A wasp sting is basic and a bee sting is acidic. What could you put on a wasp sting to neutralize it? And what could you put on a bee sting to neutralize it?
- We launder in the hottest water possible for a particular fabric. What is the chemical reason behind this? (heat speeds up reactions, helping the detergent to work)
- Why is your saliva basic? How does this help with digestion? How does this help your teeth stay healthy?
- If you’re feeling ambitious, have your kids make homemade soap out of wood ashes and grease, like people a hundred years used to do.
- Have your kids do the laundry all the time now that they know how!