The document summarizes key concepts about acids and bases: - The pH scale measures how acidic or alkaline a substance is from 0-14. Phenolphthalein and bromothymol blue are acid-base indicators that change color with pH. Universal indicator can be used to test an unknown solution's pH. - Strong acids have a pH of 0-1 and strong bases 13-14. Acids contain H+ ions and bases contain OH- ions. Common acids include citrus fruits and milk while cleaners contain bases. - Neutralization is adding a base to an acid until the pH is close to 7. Carbon dioxide forms carbonic acid in water.