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RE: How Much Silver Nitrate in Solution?



>From Wilson's Quarter Century in Photography published in 1887

I've left it to the reader to translate the units to whatever modern ones
may be desired.

Dissolve 55 grains of well dried salt in one pint of water.  (This means
non-iodized)

Measure 1/2 ounce of the solution to be tested into a sufficiently large
bottle, 8 ounces was suggested.

Add the salt test solution to it in small doses and shake well.  Continue
adding until no more cloudiness is generated.

Each ounce of test solution so used is equivalent to 10 grains of silver
nitrate to the ounce in the original solution.

What appears to make this work ok is Wilson's assertion that the bulky
silver chloride precipitate will become dense and settle rapidly when the
last required amount of salt solution is added.  He recommends adding the
last bits in 1/8 ounces increments.

This whole thing amounts to a crude titration but his 1887 claim is that it
is accurate enough for all practical purposes.

This will not work if the original solution contains lead or mercury.  If
the original is alkaline then acidify with nitric acid.

It would be easy enough to do this but I don't know if it is accurate
enough.

One small warning.  If you try to dry salt that is in big crystals over high
heat, the water can go to steam inside the crystal and, just like popcorn,
explode the crystal.  You get salt spryed all over.  So cover things.

Enjoy.

Eugene Robkin