342 DIY Science: Illustrated Guide to Home Chemistry Experiments
RQEWEvI UESTIOnS
q 1 : The precipitates produced by the anion tests take some time to settle. What alternative procedures might you use to minimize
the time necessary?
q: 2 Why did we wash the precipitate in step 10?
q: 3 If silver nitrate were unavailable to you, what alternative reagent or reagents might you use to detect and discriminate among
the halide anions? (Hint: look up the solubility of the various halide salts to find other insoluble halides.)
oALIpToN ACTIvITIES
If you have time and the required materials, consider performing these optional activities:- Have a friend or lab partner make up an unknown anion sample solution for you. Test that solution to determine which
anions are present. - Use the ammonium molybdate reagent to test a sample of laundry detergent labeled “phosphate-free” or “low phosphates”
for the presence of phosphate ions. Compare your observations with those you make using the same reagent to test a
sample of “ordinary” laundry detergent. - Use the ammonium molybdate reagent to test for the presence of phosphate ions in any solid or liquid fertilizers or plant
foods that you have access to. After you run the tests, compare your results to the contents listed on the product label. You
can also test soil samples from around the yard (a flower bed is a particularly likely candidate). - Nutrient pollution is a major source of fouling in ponds and inlets. Try testing water samples from such sources for
phosphates and nitrates. Until recently, a significant percentage of phosphate pollution in standing water originated from
phosphates in laundry detergents. The ban on phosphates in detergents means that most phosphate pollution in standing
natural waters originates from phosphates in fertilizers.