2.1. The lithium ion in a 250,00 mL sample of mineral water was precipitated with sodium tetraphenylboron:
Lit + B(C6H4)4 — LiB(CH3)4(s)
The precipitate was filtered, washed and re-dissolved in an organic
solvent. An excess of mercury (II) EDTA chelate was added:
4HgY2- + B(C6H4)4 + 4H20 =H3BO3 + 4C6H5Hg+ + 4HY3- + OH
The liberated EDTA was titrated with 29,64 mL of 0,05581 M Mg2+.
Calculate the lithium ion concentration in ppt.