Usenet Nutter wrote:
On Sat, 02 Jan 2010 14:32:48 +0000, Dave Osborne
wrote:

http://www.lpchemicals.com/product.p...ater+LR&Id=363

Thx for that ..Dunno what the "5 Water LR" means though .

I'm not an expert but I think it means that it's the pentahydrated
(crystalline) form rather than the anhydrous (powder) form; i.e. it
contains water of crystallisation. I can't see that it matters in your
application although it might if you were assaying silver content by weight.

If you're really bothered try:

http://en.wikipedia.org/wiki/Sodium_hyposulfite

Another Dave