Difference between common acid base indicator and universal indicator

Dear Student,

Acid-base indicators

i). A substance which liberates H positive ions when dissolved in water is an acid.

ii). A substance which liberates OH negative ions in water is called a base.

iii). Some natural and synthetic dyes show two different colors in acidic and base solution, and such dyes are acid- base indicators.

iv). Blue and red litmus paper are used to the acid or base.

Universal indicators

i).A universal indicator is made by mixing several synthetic indicators in specific proportions.

ii). In the pH scale,the pH of solution varies from 0 to 14 in accordance with the strength of the acid or base.

iii). To show these variation in pH,a universal is used.A universal indicator shows different colors at different values of pH.

iv). The pH of a solution can be determined by means of universal indicator solution or the pH paper made from it.

v). However, the most accurate method of measuring the pH of a solution is to use an electrical instrument called pH meter.


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Both litmus paper and the universal indicator are used in the lab oftenly!Some tests, involve only the knowledge of the nature of the substance: acidic or basic! Thus litmus paper is used to find Wether the substance is acidic or basic.If substance changes blue litmus red?.indicates the presence of acid.If substance changes red litmus blue?..indicates the prescence of base.Universal indicator is used for knowing the pH of a substance. We can not only find out nature of substance but also tell about the strenght of an acid or base. Usuallh the pH paper in dipped in the substance and compared with the pH chart and the pH value is found. If pH value is less than 7, the substance is acidic. If pH value is more than 7, then the substance is basic.Lower the value of pH, stronger the acid it is. More the value of pH, stronger the base it is.
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