If you put a red piece of litmus paper into a base the wet part of the litmus will turn blue. Then if you put a blue piece of litmus into an acid the wet part of the paper will turn red. One problem if you put red litmus and blue litmus into certain substances neither piece of litmus will change colors. They also neutralize bases in neutralization.
Acids corrode active metals.
Normally taste sour. Bases release hydroxide into water solution. Bases neutralize acids in neutralization reaction. Bases denature protein.