Betekenis van:
phenolphthalein

phenolphthalein
Zelfstandig naamwoord
    • a laxative used in many preparations under various trade names; also used as an acid-base indicator in titrations involving weak acids and strong bases because it is brilliant red at high alkalinity and colorless below pH 8

    Hyperoniemen


    Voorbeeldzinnen

    1. Phenolphthalein will turn fuchsia in the presence of a base with a pH of or above 10.0 and will remain colorless in the presence of a solution with a pH of or below 8.2.
    2. phenolphthalein
    3. Phenolphthalein
    4. Phenolphthalein solution, c = 2 g/100 ml in ethanol (3.1).
    5. Phenolphthalein solution, c = 2 g/100 ml in ethanol (3.1)
    6. Ethanol solution 40 % (v/v) density: 0,948 g/ml at 20 oC, neutralised to phenolphthalein.
    7. Neutralisation of 1 g of calcium benzoate, in the presence of phenolphthalein, must not require more than 0,25 ml of 0,1 N NaOH or 0,1 N HCl
    8. Neutralisation of 1 g of potassium benzoate, in the presence of phenolphthalein, must not require more than 0,25 ml of 0,1 N NaOH or 0,1 N HCl
    9. Dissolve 1 g of potassium lactate solution in 20 ml of water, add 3 drops of phenolphthalein TS and titrate with 0,1 N sodium hydroxide.
    10. Neutralisation of 1 g of sodium benzoate, in the presence of phenolphthalein, must not require more than 0,25 ml of 0,1 N NaOH or 0,1 N HCl
    11. Dissolve 1 g of potassium lactate solution in 20 ml of water, add 3 drops of phenolphthalein TS and titrate with 0,1 N sodium hydroxide. Not more than 0,2 ml should be required
    12. Wash the combined extracts in the separating funnel twice by gently swirling (to avoid formation of emulsions) with 100 ml portions of water and then by repeated shaking with further 100 ml portions of water until the water remains colourless on addition of phenolphthalein solution (3.7) (washing four times is usually sufficient).
    13. Repeat this extraction twice, with 100 ml light petroleum (3.2) and twice, with 50 ml light petroleum (3.2). Wash the combined extracts in the separating funnel twice by gently swirling (to avoid formation of emulsions) with 100 ml portions of water and then by repeated shaking with further 100 ml portions of water until the water remains colourless on addition of phenolphthalein solution (3.7) (washing four times is usually sufficient).