Question
Phosphates are essential nutrients for plants. They are one of several substances which can promote the growth of algae in natural waters, and may be partially responsible for contributing to eutrophication in lakes and ponds. The same procedure used in this experiment can be used to measure the concentration of phosphates in water. a. Dilbert Dingle wanted to analyze a sample of his well water for phosphate content. The first time he analyze a sample, he forgot or add the molybdate/metavanadate reagent to the water sample. What %T reading did he get on the spectrophotometer? Why?
Explanation / Answer
On adding the molybdate/metvanadium reagent, the phosphate will form yellow vanadomolybdophosphoric acid is formed, the intensity of which is directly proportional to the amount of phosphate present. If we are not adding the reagent no light is absorbed and we will end up with 100% transmittance.