Chem Question~THX

1) Standardization of EDTA can be done by titration against standardized NaOH solution with suitable pH indicator. The standardized NaOH solution is made by weighing exact amount of NaOH in dry air and dissolve the NaOH into pure water.

2) The commonly used definition of water hardness refers to the amount of magnesium and calcium dissolved in water. It is one of the key properties needed to be determined for many chemical and biological purposes. For example, the hardness of water could affect the efficiency of a industrial process. Also, the hardness of water could affect the toxicity of a toxicant to aquatic organisms.

3) Chelation Therapy refers to the removal of metals from the body by the use of chemical(s). As a chelating agent, ETDA can be brought into human's blood vessel to removal metals from the body throught urination. As a result, EDTA is often used in chelation therapy for heavy metal poisoning. Yet, supplements of other essential metals are required as the therapy bring out essential metals such as calcium and zinc as well.