Acids and bases react with each other in a reaction called neutralization. O Acids and bases have some general properties. Many acids have a sour taste. Citric acids, found in oranges and lemons, is one example where the sour taste is related to the fact that the chemical is an acid. Molecules that are bases have a bitter taste, like caffeine.
Bases make solutions that are slippery.
Many acids will react with metals to dissolve the metal and at the same time generate hydrogen gas, H 2 . The most obvious ability of acids and bases is their ability to change colors of certain other chemicals. Commonly, an extract of lichens called litmus has been used since it turns blue in the presence of bases and red in the presence of acids. Extracts made from red onions, red cabbage, and many other fruits and vegetables change colors in the presence of acids and bases. Such materials are called indicators.