Very good. For that you get a Practical household Degree or PhD,
Most things wine red, blue, or yellow in food, are indicators of acidity or baseness. Most contain anthocyanins.
Beets and Wine can be added to that list.
Chlorine in water and Javex is a weak acid.
Vinegar and lemon juice are weak acids.
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Baking soda, NaHCO3, fizzes when added to an acidic
solution, but no change occurs in basic solution. The reaction is:
HCO3-(aq) + H+(aq) = H2O() + CO2(g)
The reaction isn't easily reversible so baking soda is more of a "spot test" for acids than an indicator.
Beets change from red to purplish in very basic solution.
Blackberries, black currants, and black raspberries change
from red in acids to dark blue or violet in basic solution.
Blue and red grapes contain several different pH-sensitive anthocyanins. For example, blue grapes are colored by a monoglucoside of malvinidin that changes from deep red in acidic solutions to violet in basic solution. Red wines naturally contain these same pigments.
Blueberries change from blue (around pH 2.8-3.2) to red in a
strongly acidic solution.
Carrots
Cherries and cherry juice is bright red in acidic solution but purple to blue in basic solution.
Cranberries
Curry powder and tumeric are spices that contain a bright yellow pigment called curcumin (which is not an anthocyanin). It turns from yellow at pH 7.4 to red at pH 8.6.
Delphinium petals contain an anthocyanin called delphinin, which changes from bluish red in acid to blue to violet in basic solution.
ExLax tablets contain phenolphthalein. The powdered tablets change from colorless under pH 8.3 to pink to a deep red above pH 9.
Geranium petals contain pelargonin, an anthocyanin which changes from orange-red in acid solution to bluish in basic solution.
Horsechestnut leaves can be ground with alcohol to extract esculin, a fluorescent dye. Esculin changes from colorless at pH 1.5 to fluorescent blue at pH 2. Shine a black (ultraviolet) light on the indicator to get the full effect.
Mood lipsticks undergo many interesting pH-related color
changes.
Morning glories contain an anthocyanin called "heavenly blue
anthocyanin" which changes from purplish red at pH 6.6 to blue at pH 7.7.
Onion is an olfactory indicator. The onion odor isn't detectable in strongly basic solutions. Red onion can act as a visual indicator at the same time. It changes from pale red in acid solution, to green in basic solution.
Pansy petals
Petunia petals contain petunin, an anthocyanin that changes from reddish purple in acid to violet in basic solution.
Poison primrose (Primula sinensis) has both orange and blue
flowers. The orange flowers contain a mixture of pelargonins
(the same type of pigment found in geraniums). The blue
flowers contain malvin (similar to the pigment in blue grapes),which turns from red to purple as a solution changes from acidic to basic.
Poppy flower petals Purple peonies contain peonin, which changes from reddish purple or magenta in acid solution to deep purple in basic solution.
Red cabbage contains a mixture of anthocyanins and other pigments that indicate a wide range of pH. Red cabbage juice changes from deep red at pH 1 to purple at pH 7 to to green at pH 12. At higher pH (13-14) it turns yellow.
Red radish
Rhubarb
Rose petals contain the oxonium salt of cyanin, and they turn blue in basic solution. (The potassium or calcium salt of the same pigment makes cornflowers blue!)
Strawberries
Tea
Thyme(extract in alcohol)
Tulip petals
Vanilla extract, like onion, is an olfactory indicator. The vanilla odor isn't detectable in strongly basic solution because vanillin exists in ionic form at high pH.
Violet petals
Washing soda, like baking soda, fizzes when added to an acidic solution. No change occurs in basic solution. The reaction is
CO32-(aq) + 2 H+(aq) = H2O() + CO2(g)
References
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1.P. W. Atkins, Molecules ,W. H. Freeman, Oxford, England, (1987).
2.K. C. Li, A. C. Wagenknecht, "Anthocyanin Pigments Of Sour
Cherries", Journal Of The American Chemical Society, 78, 979 (1956).
3.F. J. Francis, J. B. Harborne, W. Barker, "Anthocyanins In The Lowbush Blueberry, Vaccinium Angusifolium", Journal Of Food Science, 31, 583 (1966).
4.T. Fuleki, "The Anthocyanins Of Strawberry, Rhubarb, Radish And Onion", Journal Of Food Science, 34, 365 (1969).
5.A. Lukton, C. O. Chichester, G. Mackinney, "Characterization Of A Second Pigment In Strawberries", Nature, 176, 790 (1955).
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