3 Litmus Paper + Substitutes
The red litmus paper remains red if it is an acid. It will turn blue in the presence of a base.
The blue litmus paper remains blue if it is a base. It will turn red in the presence of an acid.
If the red or blue litmus paper are placed in a neutral solution, both litmus papers will remain their original colors.
Helpful Hint: Blue indicates a base. Both words start with “b”.
Sometimes when investigating the properties of a liquid or solution, it is both difficult and dangerous to use the five senses to determine if it is an acid or base. These simple tests are safer.
Other liquids that may be used include: shampoo, coffee, pop, baking soda and water, cream of tarter and water, ketchup.
How to make your own indicator solutions:
The juices of some vegetables andother plants will work as litmus test indicators for acids and bases.
Red cabbage is cooked until it is tender, and its juice is strained into a jar. When a little of this juice is added to an acid, such as vinegar, it will become redder. In a base, such as ammonia, it will turn towards blue or green.
Beet juice will also react in this way, but not quite so well as the cabbage.
The spice turmeric will turn from yellow to red when a bit of the powder is added to a base.
Indicators are usually more reactive if they are made by the "alcohol" method.
With cabbage, for example, shred the leaves and cover them with rubbing alcohol. Let stand until the alcohol has become a deep red. Strain out the cabbage leaves. When an acid is added, the red color will deepen. If a base is added it should turn green.
Other plant juices such as cherries, beets, and blueberries work as well. Apparently the leaves of the poinsettia (toxic!) and carnation flowers will also work, but let's leave the toxic plants alone!