Commercial indicators can be used to test whether a substance is acidic or basic. The following experiment shows what is observed when commercial indicators are added to different acids and bases. Dilute Hydrochloric acid is placed in test-tube 1, 2 and 3 while ammonia solution is placed in test-tube 4,5 and 6.Two drops of methyl orange is added to test-tube 1 and 4. Two drops of phenolphthalein indicator are added to test-tube 2 and 5. Blue and red litmus papers are placed intotest-tube3 and 6