The color that a substance turns a pH indicator is a characteristic property of that substance. An acid can neutralize a base, and a base can neutralize an acid Students squeeze red cabbage leaves in ...

Make your own acid-base indicator from red cabbage, then test various household substances. Acids and bases are classes of materials that have different properties. Acid-base indicators change color ...

Bacteria that have the enzyme tryptophanase, can convert the amino acid, tryptophane to indole. Indole reacts with added Kovac’s reagent to form rosindole dye which is red in color (indole +).