Question

What is the color of the solution when a drop of stannous chloride is added to one of the standard ammonium molybdate and phosphate solution?

	a.	Orange
	b.	Blue
	c.	Red
	d.	Green
	e.	Yellow

Answer 1

Answer: b Blue

Explanation:

A Quantitative method to determine the amount of phosphate present in samples such as boiler feedwater is as follows. A measured amount of boiler water is poured into a mixing tube and ammonium heptamolybdate reagent is added. The tube is then stoppered and vigorously shaken. The next step is to add dilutestannous chloride reagent, which has been freshly prepared from concentrated stannous chloride reagent and distilled water, to the mixture in the tube. This will produce a blue color (due to the formation of molybdenum blue) and the depth of the blue color indicates the amount of phosphate in the boiler water.