Phenolphthalein is an indicator that turns from clear to pink in a basic solution, according to Reference.com. In a strongly acidic solution, the indicator is orange, but in the pH range of 0 to 8.2 it is clear. The indicator is pink in solutions with a pH of 8.2 to 12, but turns colorless again in strong bases above this pH range.Continue Reading
Reference.com indicates that phenolphthalein is a weak acid itself that in molecular form is colorless. The addition of a base to a solution of phenolphthalein removes hydrogen ions from the solution, creating more phenolphthalein ions, which causes the color to change.
Chemists use titrations to determine the concentration of an unknown acid or base. They add the opposite reagent of known concentration and carefully measure the amount needed to cause the color change. About.com says, "For a properly performed titration, the volume difference between the end point and the equivalence point is small." At the equivalence point, V1N1 = V2N2, where V is volume and N is the concentration of the acid or base.
Reference.com says that universal indicators are a mix of phenolphthalein, and the indicators methyl red, bromothymol blue, and thymol blue. By mixing several indicators, chemists create a single solution that is useful in determining pH over a wide range.Learn more about Chem Lab
Perform an acid-base titration in the lab by setting up a burette, dissolving the material for analysis in water in a flask, adding an indicator, recording an initial reading of the burette, adding titrant until the color changes and taking the final reading. The experiment usually takes less than an hour.Full Answer >
Colors on a universal indicator pH chart include: red, orange and yellow for acids, light green for neutral, and green, blue and violet for bases. The universal indicator chart assigns a color to each pH level on a scale of four to 10 pH.Full Answer >
The function of an indicator in a titration process is to determine the equivalence point when two solutions have reached neutralization. An indicator can either be internal or external. An internal indicator is mixed in with the reactants and typically provides a visual prompt, while an external indicator is an electrochemical apparatus.Full Answer >
Sodium chloride salt crystals can be grown from table salt dissolved in water by allowing the solution to evaporate undisturbed. It is believed that dissolved sea salt or pickling salt, which is pure salt, produces larger crystals while iodized salt appears to promote the growth of smaller crystals. Allowing the evaporation process to go undisturbed is important because any ripples that occur in the solution while it is in the growing container will cause the forming crystals to be smaller.Full Answer >