Search results
Results from the WOW.Com Content Network
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H + ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further proton loss in higher pH occurs slowly and leads to a colorless form.
Solution: The main components of a universal indicator, in the form of a solution, are thymol blue, methyl red, bromothymol blue, and phenolphthalein. This mixture is important because each component loses or gains protons depending upon the acidity or alkalinity of the solution being tested. It is beneficial to use this type of universal ...
In acid-base titrations, an unfitting pH indicator may induce a color change in the indicator-containing solution before or after the actual equivalence point. As a result, different equivalence points for a solution can be concluded based on the pH indicator used.
Titration of a standard solution using methyl orange indicator. Titrate is in Erlenmeyer flask, titrant is in burette. acid + base → salt + water. For example: HCl + NaOH → NaCl + H 2 O. Acidimetry is the specialized analytical use of acid-base titration to determine the concentration of a basic (alkaline) substance using standard acid.
For example, the titration curve for the titration between oxalic acid (a weak acid) and sodium hydroxide (a strong base) is pictured. The equivalence point occurs between pH 8-10, indicating the solution is basic at the equivalence point and an indicator such as phenolphthalein would be appropriate.
During many titrations, the conductivity changes significantly. (For instance, during an acid-base titration, the H 3 O + and OH − ions react to form neutral H 2 O. This changes the conductivity of the solution.) The total conductance of the solution depends also on the other ions present in the solution (such as counter ions).
Animation of a strong acid–strong base neutralization titration (using phenolphthalein). The equivalence point is marked in red. In chemistry, neutralization or neutralisation (see spelling differences) is a chemical reaction in which acid and a base react with an equivalent quantity of each other. In a reaction in water, neutralization ...
A weak acid or the conjugate acid of a weak base can be treated using the same formalism. Acid HA: HA ⇌ H + + A −; Base A: HA + ⇌ H + + A; First, an acid dissociation constant is defined as follows. Electrical charges are omitted from subsequent equations for the sake of generality