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indicators, acid-base

acid-base indicators, organic compounds that, in aqueous solution, exhibit color changes indicative of the acidity or basicity of the solution. Common indicators include p-nitrophenol, which is colorless from pH 1 to 5 and yellow from pH 5 to 9; methyl orange, yellow in basic and neutral solutions and reddish below pH 3.7; phenolphthalein, colorless in acid and neutral solutions, pink at about pH 8.5, and purplish at pH 10; and litmus. Most indicators are also used in large amounts for dyeing; small quantities are nonetheless invaluable for use as indicators in chemical laboratories.

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"indicators, acid-base." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 21 Sep. 2017 <http://www.encyclopedia.com>.

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"indicators, acid-base." The Columbia Encyclopedia, 6th ed.. . Retrieved September 21, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/indicators-acid-base

acid-base indicators

acid-base indicators: see indicators, acid-base.

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"acid-base indicators." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 21 Sep. 2017 <http://www.encyclopedia.com>.

"acid-base indicators." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (September 21, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/acid-base-indicators

"acid-base indicators." The Columbia Encyclopedia, 6th ed.. . Retrieved September 21, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/acid-base-indicators