ScienceHideout - 1-7-2012 at 06:45
Hi!
For school I need to do some research on silver colloids. In order to supplement my research, I need to answer a few questions, like how much silver
is formed. Yes, it is quite easy to do stuff like this- as I do have a milligram balance, so I measured the amount of silver in the precipitate and
the amount of silver that is on the wall of the test tube. However, I am trying to think of a way to measure the amount of silver in the colloid. My
first idea was to titrate it with nitric acid, but I decided against it. My second idea is to try to destabilize the colloid and make ALL the silver
precipitate out.
Anyways- my idea is to add a chemical to break the Van der Waal's force. Maybe H2SO4? That is what I am asking. Does anyone know how to destabilize
this colloid?
Thanks in Advance!
P.S. I am centrifugeless
barley81 - 1-7-2012 at 11:15
You could react a known amount of the silver suspension with nitric acid and titrate it against a known amount of NaCl solution using
dichlorofluorescein as an indicator. Before the endpoint, the suspension appears green, but after the endpoint, Ag+ ions adhere to the surface of the
AgCl particles. The positively charged particles attract the anion of dichlorofluorescein, and the suspension turns pink.
Ask your school to order some of the indicator. That is the good part about working in a school.