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A chemical indicator is a substance that undergoes a distinct observable change when conditions in its solution change. This could be a color change, precipitate formation, bubble formation, temperature change, or other measurable quality. Another type of indicator that may be encountered in chemistry and other sciences is a pointer or light on a device or instrument, which may show pressure, volume, temperature, etc. or the condition of a piece of equipment (e.g., power on/off, available memory space). The term "indicator" comes from the Medieval Latin words indicare (to indicate) with the suffix -tor. Examples of Indicators
Desirable Qualities of a Chemical IndicatorTo be useful, chemical indicators must be both sensitive and easily detectable. It need not, however, show a visible change. The type of indicator depends on how it's being used. For example, a sample analyzed with spectroscopy may employ an indicator that wouldn't be visible to the naked eye, while a test for calcium in an aquarium would need to produce an obvious color change. Another important quality is that the indicator doesn't change the conditions of the sample. For example, methyl yellow adds a yellow color to an alkaline solution, but if acid is added to the solution, the color remains yellow until the pH is neutral. At this point, the color changes from yellow to red. At low levels, methyl yellow does not, itself, change the acidity of a sample. Typically, methyl yellow is used at extremely low concentrations, in the parts per million range. This small amount is sufficient to see a visible change in color, but not enough to change the sample itself. But what If an enormous amount of methyl yellow were added to a specimen? Not only might any color change be invisible, but the addition of so much methyl yellow would change the chemical composition of the sample itself. In some cases, small samples are separated from larger volumes so that they can be tested using indicators that produce significant chemical changes. What is an indicator and examples?Indicators are weak acids or weak bases that show a change in colour as the concentration of Hydrogen ions in a solution changes or the pH of a solution changes. The indicators dissociate slightly in the water to form ions. Some examples of indicators are Litmus, turmeric, phenolphthalein, etc.
What are indicators easy definition?Definition of indicator
1 : one that indicates: such as. a : an index hand (as on a dial) : pointer. b(1) : gauge sense 2b, dial sense 4a. (2) : an instrument for automatically making a diagram that indicates the pressure in and volume of the working fluid of an engine throughout the cycle.
What is a indicator in natural science?Natural Indicator is a type of indicator that can be found naturally and can determine whether the substance is an acidic substance or a basic substance. Some examples of natural indicators are red cabbage, turmeric, grape juice, turnip skin, curry powder, cherries, beetroots, onion, tomato, etc.
What are the 3 types of indicators?Indicators can be described as three types—outcome, process or structure - as first proposed by Avedis Donabedian (1966).
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