Question

Prior to the 1970s, lead pipes were used for household water piping. Most older homes have had their piping changed to copper or plastic, but some homes still have lead piping.

Your roommate is concerned about possible lead exposure and has requested your help to determine the concentration of lead in your tapwater. You collect a 750 mL sample of tapwater to analyze and bring it to the lab.

Using aliquots of 10 mL, you performed the following procedures: 18.0 mL of 0.09 M EDTA was added to the alliquot which reacted with the Pb in solution.

The solution was then titrated with 0.050 M Cu solution. 10.1 mL of Cu was required.

Calculate the concentration of lead in your tapwater

Answer 1

edra Here excess is added and then. back Atvated with known cu solution Cor EDTA - CU-EDTA complex moles of coveached moes of EDTA excess Cexcess = OoJom x10-1ml 0.505 mmoles. Total moles of EDTA added a (Mauzora 20.09m x 18.0ml 2 1-62 mmoles Pb + FOTA - PL-EDTA complex mmoles of EDTA reacted with Pb. in Totalmmoles – mnoles et FOTA (excess) 2 mxv) EDTA 1.62 mmoles - 0.505 mmoles - 115 mmoles = 2 10ml & m x 1.115 mmoles Pb 1.115 mmoles 10mL 0. 1115 ~ Tollm) concentration of u lead in top citer