Titrations

Titration

Method for determining the concentration of an unknown solution

A measured volume of a solution of known concentration (titrant) is delivered to a solution of unknown concentration (analyte)

Equivalence point is where exactly enough titrant is added to react with the analyte

Indicator is marked by an indicatorEquivalence is where the indicator changes

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Example

An environmental chemist analyzed the waste material from an industrial process. The material is known to contain carbon tetrachloride and benzoic acid (HC7H5O2). A sample of the waste weighing .3518g was shaken with water and the resulting solution required 10.59 ml of .1546M NaOH for neutralization. What percent of the sample was benzoic acid?

Standardization

Titration procedure used to determine the exact concentration of a solution

Standardization Example

A student weighs out a 1.3009g sample of KHC8H4O4 (KHP) and dissolves it in distilled water. Phenolphthalein indicator is then added and the solution is titrated with an NaOH solution until the endpoint. The difference between the initial and final buret readings is 41.20ml. Calculate the concentration of the NaOH solution.

Inquiry Lab

Develop a procedure for the standardization of sodium hydroxide solution using between 0.40 and 0.60 g of KHP

Multiple trials (at least 3) must be carried out with the results varying by no more than two standard deviations

Report your standardized molarity in the form____M ± ___ M