STP FOR COPPER SULFATE

nirvesh400

1.0) Description: Greenish-grey powder, very hygroscopic.

2.0) Solubility: Freely soluble in water, slightly soluble in methanol, practically insoluble in

ethanol (96 per cent).

3.0) Identification:

  1. A. Add several drops of dilute ammonia R2 1 mL of solution S . A blue precipitate is formed, On further addition of dilute ammonia R2 the precipitate dissolves and a dark blue colour is produced.
  2. B. Loss on drying .
  3. C. Dilute 1 mL of solution S to 5 mL with water R.

The solution gives reaction (a) of sulfates .

4.0)     Tests:

4.1)     Solution S

Dissolve 1.6 g.in water R and dilute to 50 mL with the same solvent.

4.2)    Appearance of solution

Solution S is clear .

4.3)    Chlorides

Maximum 150 ppm.

Dilute 10 mL of solution S to 15 mL with water R.

4.4)     Iron

Maximum 150 ppm.

Atomic absorption spectrometry .

Test solution Dissolve 0.32 g in 10 mL of water R, add 2.5 mL of lead-free nitric acid R and

dilute to  25.0 mL with water R.

Reference solutions Prepare the reference solutions using iron standardsolution (20 ppm Fe)

R, adding 2.5 mL of lead-free nitric acid R and diluting to 25.0 mL with  water R.

Source Iron hollow-cathode lamp.

Wavelength 248.3 nm.

Atomisation device  Air-acetylene flame.

Copper may form explosive acetylides with acetylene. Therefore, clean the burner

thoroughly before any residues become dry.

4.5)    Lead

Maximum 80 ppm.

Atomic absorption spectrometry .

          Test solution Dissolve 1.6 gin 10 mL of water R, add 2.5 mL of lead-free nitric acid R

and  dilute to 25.0 mL with water R.

          Reference solutions Prepare the reference solutions using lead standard  solution

(l00 ppm Pb) R, adding 2.5 mL of lead-free nitric acidRand diluting to 25.0 mL with water R.

           Source Lead hollow-cathode lamp.

Wavelength  217.0 nm.

Atomisation device Air-acetylene flame.

Copper may form explosive acetylideswith acetylene. Therefore, clean the burner

Thoroughly  before any residues become dry.

4.6)     Loss on drying

Maximum 1.0 per cent, determined on 0.500 g by drying in an oven at 250 ± 10 “C.

4.7)    Assay

Dissolve 0.125 gin: 50 mL of water R. Add 2 mL of sulfuric acid Rand 3 g of potassium

iodide   R. Titrate with 0.1 M sodium thiosulfate, using 1 mL of starch solution R towards

the  end of the titration.

1 mL 0.1 M sodium thiosulfate is equivalent to 15.96 mg of CuSO4.

 

 

STP