Indicators are substances that change color based on pH levels in solutions, acting as visual indicators of acidity and alkalinity. They are usually weak acids or bases whose conjugate forms have different colors, allowing the pH of a solution to be determined visually. A pH indicator detects hydronium or hydrogen ions and causes the solution's color to change based on its pH value, with values below 7.0 indicating acidity and above indicating alkalinity, while a neutral solution has a pH of 7.0.

1. INDICATORS
 Indicators are substances
whose solutions change
color due to changes in pH.
These are called acid-base
indicators.

2. INDICATORS
They are usually weak acids or
bases, but their conjugate
base or acid forms have
different colors due to
differences in their absorption
spectra

3. INDICATORS
A pH indicator is a
halochromic chemical
compound added in small
amounts to a solution so the pH
(acidity or basicity) of the
solution can be determined
visually.

4. INDICATORS
A pH indicator is a basically a
chemical detector for hydronium
ions (H3O+) or hydrogen ions
(H+) in the Arrhenius model
Normally, the indicator causes
the color of the solution to
change depending on the pH

5. INDICATORS
The pH value of a neutral
solution is 7.0 at 25°C (standard
laboratory conditions)
Solutions with a pH value below
7.0 are considered acidic and
solutions with pH value above
7.0 are basic (alkaline)