pH Chemical Indicators
pH paper is treated with a chemical indicator that changes in the presence of hydroxide or hydrogen ions. Such chemical indicators can be found in foods such as red cabbage, strawberries or blueberries, to name a few.
Why the Color Change
This pH paper changes color in different pH solutions because of the chemical flavin, which is a pigment present in red cabbage. This molecule, which is an anthocyanin, is soluble in water and changes color in the presence of various types of solutions. In the presence of an acidic solution, it turns red. In the presence of a basic solution, it turns greenish. In the presence of a neutral solution, it turns purple.
General Color Changes
When flavin-treated pH paper is dipped into a vial of an acidic solution, such as hydrochloric acid, or HCl, it turns red. When it's dipped into a vial of sodium hydroxide, or NaOH, which is basic, it turns a greenish color. When pH paper is in the presence of pure water, it turns purple. Note that litmus paper only turns two colors: red for acids and blue for bases.
pH Chemical Indicators
pH paper is treated with a chemical indicator that changes in the presence of hydroxide or hydrogen ions. Such chemical indicators can be found in foods such as red cabbage, strawberries or blueberries, to name a few.
Why the Color Change
This pH paper changes color in different pH solutions because of the chemical flavin, which is a pigment present in red cabbage. This molecule, which is an anthocyanin, is soluble in water and changes color in the presence of various types of solutions. In the presence of an acidic solution, it turns red. In the presence of a basic solution, it turns greenish. In the presence of a neutral solution, it turns purple.
General Color Changes
When flavin-treated pH paper is dipped into a vial of an acidic solution, such as hydrochloric acid, or HCl, it turns red. When it's dipped into a vial of sodium hydroxide, or NaOH, which is basic, it turns a greenish color. When pH paper is in the presence of pure water, it turns purple. Note that litmus paper only turns two colors: red for acids and blue for bases.
pH paper is impregnated with Flavin,which shows colour change when exposed to acid media or alkaline media.
in pH paper there is an coating of anthocynin which is Flavin. It shows color change in acidic or alkaline media.
Is only anthocynin (flavin) present or many others compounds present? If anthocynin gives two colors one in acidic and one in basic? What about others?
why does high concentration [40% and +] cause a delay in the pH paper to turn color? i know it is 14, , the color turns darker than what is indicated for 14, but why does it take so much longer than for lower concentrated NaOH solutions?
pH measurement is necessary requirement in any chemical reaction. What is the standard composition for the preparation of solution for finding pH in test tube?
In the answer Flavin/anthrocynin mentioned but at what quantity and in what medium?
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