CH111- Lab 2

Read chapters 6 and 10 of Skoog, et.al. for relevant information. (Chapter 25 in the 6th edition)
For acid-base information, refer to Hill 4.2
For the structure of benzene derivatives, refer to Hill 10.9
For ion exchange, refer to Hill 20.12

Be sure to use the CORRECT CONCENTRATION of NaOH at the proper time!!

Main idea of the lab- find chloride content (NOTE: NOT the composition) of an unknown by ion exchange....replace hydroxide on a column with chlorides of unknown...acidify this solution with a known volume of acid of known concentration.... neutralize this acid with base of known concentration. Amount of base needed equals amount of acid used in second step MINUS the amount of hydroxide washed off the column...this amount gives the amount of chloride in the original solution. Then it's just a matter of calculating the dilution of the unknown added to the column.

Anything which serves to alter amount of hydroxide washed off column or neutralized by acid is a source of error.

HINT: We do NOT standardize the NaOH "to determine the concentration of the NaOH exactly"...that is simply stating the DEFINITION of standardization.

Do not forget to compare this method with gravimetric in your conclusion (and summarize in abstract).

Among others, topics to be sure you cover in your report: chlorine and chloride again, ion exchange, primary standard, amphoteric compounds

Send questions or comments to Professor Kolack via email (kolack AT cooper DOT edu)
© 1999-2008 Dr. Kevin Kolack; may not be copied, reproduced and/or placed on file without written permission from the author