Unknown Acid Problem

Your company has just purchased a warehouse containing an old chemistry laboratory, and the first order of business is to take inventory of the chemicals in the stockroom so that you can properly dispose of them according to current EPA regulations. Unfortunately, the previous chemist was lazy, and some of the bottles are not labeled thoroughly. Of particular concern are two bottles marked simply "acid" with no further information. Fortunately you find an old lab notebook with a table of acids used by the previous chemist.

You decide that you can collect some experimental data which will enable you to both (1) identify the unknown acids by comparison with the lab notebook information, and (2) determine their concentrations. Since the disposal of unidentified chemicals is more expensive than that of known compounds, a few hours of lab work can translate into considerable savings for your company.

Acid	pK_a
crotonic	4.69
methylmalonic	3.07
diphenylacetic	3.94
picric	strong
alloxanic	6.64
methyl-m-aminobenzoic	5.10

Activity 1 Use the Virtual Lab to identify the contents and concentration of the first bottle.

Activity 2 Use the Virtual Lab to identify the contents and concentration of the second bottle.

Later in your inventory process, you come across another bottle labeled "mixed trichloroacetic and alloxanic acids". Looking up these compounds in a chemistry handbook, you find that the trichloroacetic is a strong acid and the K_a for alloxanic acid is 2.3 x 10^-7.

Activity 3 Use the Virtual Lab to determine the concentrations of the two acids in this bottle.

Please take detailed notes of your procedure, and complete a report of your experiment(s) to be turned along with printed copies of the pages that state that the problems are solved. A sample report can be found here.

Last Updated: Friday, March 4, 2005 @ 05:26:57 pm