This preview shows page 1. Sign up to view the full content.
Unformatted text preview: 2 O 2 . Upon heating, the following reaction takes place: OH – + HCHO + H 2 O 2 → HCOO – + 2H 2 O After cooling, the excess NaOH was titrated with 23.3 mL of 0.05252 M H 2 SO 4 . Calculate the % w/w HCHO in the sample of pesticide. 4. Suggest an appropriate molarity of HCl if you wish to titrate 25-mL samples of nominally 0.055 M Na 3 PO 4 to the bromocresol green endpoint using between 25 mL and 35 mL of titrant. 5. The alkalinity of natural waters is assumed to arise from a combination of NaOH, Na 2 CO 3 , and NaHCO 3 . Possible combinations include NaOH alone, NaOH and Na 2 CO 3 , Na 2 CO 3 alone, Na 2 CO 3 and NaHCO 3 , or NaHCO 3 alone. Suppose you titrate a 25.00-mL sample of water with 0.1202 M HCl and find that it takes 29.64 mL to titrate to the phenolphthalein endpoint and 34.62 mL to titrate to the bromocresol green endpoint. What compound(s) is (are) responsible for the sample’s alkalinity and what is (are) its (there) concentration(s)?...
View Full Document
This note was uploaded on 04/02/2012 for the course CHEMISTRY 222 taught by Professor Mcdonald during the Fall '11 term at University of Illinois, Urbana Champaign.
- Fall '11
- Analytical Chemistry