What is an indicator?

What is an indicator ? How many types of Indicator.

Chemical indicator is any substance that gives a visible sign, usually by a colour change, of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution. An example is the substance called methyl orange, which imparts a yellow colour to an alkaline solution.

Indicators (visual) are substances that change colour when they are added to acidic or alkaline solutions. Litmus, phenolphthalein, and methyl orange are all indicators that are commonly used in the laboratory.

Additionally there are different types of chemical indicators (sterilization process)

  1. Process indicators
  2. Indicators for use in particular tests
  3. Single variable indicators
  4. Multi-variable indicators
  5. Incorporating indicators
  6. Copying indicators
    Also there are ‘Biological’ indicators used during validation of autoclaves and sterilization processes in the pharmaceuticals (sterile products manufacturing)

Thank you sir

Sir , Can we say that There are two types of Indicator mainly.
(1) Acid & (2) Alkali base indicator.


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