What are indicators and how are they used?

Indicators are substances that change color to show whether a solution is acidic or basic. Common indicators include litmus (red in acid, blue in base), phenolphthalein (colorless in acid, pink in base), and methyl orange (red in acid, yellow in base). Universal indicators give a range of colors depending on pH. Indicators are used in labs, titrations, and to test soil or water acidity. Natural indicators like turmeric and red cabbage extract also help identify pH. They provide a quick visual cue in chemistry.