Wednesday, January 5, 2011


A little diphenylamine is dessolved in 1 c.c. 90% sulphuric acid.
A drop of resgent is placed on the fabiric: deep blue indicates nitrate,
e.g. cellulose nitrate.


Schiff's reagent is made by dessolving 0.2 gm. rosaniline (fuschsine)
in 10 c.c. of cold water previously saturated by sulphur diocide. On
standing, the pink colour disappears. The reagent is kept in a dark- coloured,
stoppered bottle. The addition of aldehyde restores the pink colour.

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