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9. Plyumbum (II) acetate, 0.1 N solution. 19 g Pb
(CH 3COO) 2 dissolve in 1 liter of water. If the solution is
cloudy, add a few drops of acetate acid then make it clear.
10. Feleng reagent (feling liquid). Two solutions are
prepared - Feling I and Feling II. To prepare Felinga I, take
3
34.6 g of crystalline CuSO 4 ∙ 5H 2O and dissolve in 500 cm
of water. To prepare the Feling II solution, we weigh 173 g
of bran salt (the average sodium tartaric acid (tartaric acid
3
salt)), add 70 g sodium hydroxide and 500 cm of water.
Before use mix the same volumes of both solutions.
11. A mixture of ethanol and concentrated sulphate
acid. To 1 part of ethanol (Rectifier, 96%, d = 0.8118
3
g/cm ) carefully, with stirring and cooling add 3 parts of
3
concentrated sulfate acid (d = 1.84 g / cm ).
12. Ferum (III) chloride, 1% solution. 1 g of ferric
(III) chloride is dissolved in 100 cc of water. If the solution
is opaque, several drops of concentrated hydrochloric acid
are added to it.
13. Chromium blend. The most common two
methods of preparing a chrome mix:
3
a) 400 cm of 10% solution of potassium dichromate
3
is mixed with 100 cm of dilute (1: 1) sulfate acid;
b) 100 cm of concentrated sulfuric acid is mixed with
3
400 cm of water. To the solution add potassium
dichromate powder to full saturation.