Sodium Molybdate:

Specifications of Commercial Pure Sodium Molybdate Dihydrate:
Na2MoO4,2H2O — 241.9 — 10102-40-6
Appearance: White Crystalline Powder
Color of the solution: 10% solution in distilled water is clear and colorless
Assay: 99% minimum
MoO3 content: >58.37%
Mo content: >38.86%
pH: 9
Chloride (Cl): 0.05% maximum
Sulphate (SO4): 0.01% maximum
Iron: 50 ppm maximum
Insoluble matter: Maximum 0.02%

Sodium Molybdate Dihydrate BP Grade
Ph Eur
Na2MoO4,2H2O — 241.9 — 10102-40-6

DEFINITION
Content: 98.0 per cent to 100.5 per cent (dried substance).

CHARACTERS
Appearance: White or almost white powder or colourless crystals.
Solubility: Freely soluble in water.

IDENTIFICATION
A. Loss on drying (see Tests).
B. Dissolve 0.2 g in 5 ml of a mixture of equal volumes of nitric acid and water and add 0.1 g of ammonium chloride. Add 0.3 ml of disodium hydrogen phosphate solution and heat slowly at 50-60C. A yellow precipitate is formed.
C. Dissolve 0.15 g in 2 ml of water, the solution gives reaction of sodium.

TESTS
Solution S: Dissolve 10.0 g in water and dilute to 50 ml with the same solvent.
Appearance of solution: Solution S is clear and colourless.
Chlorides: Maximum 50 ppm.
Phosphates: Maximum 200 ppm.
Ammonium: Maximum 10 ppm, determined on 0.10 g.
Heavy metals: Maximum 10 ppm.
Loss on drying: 14.0 per cent to 16.0 per cent, determined on 1.000 g by drying in an oven at 140C for 3 h.

ASSAY
Dissolve 0.100 g in 30 ml of water, add 0.5 g of hexamethylenetetramine and 0.1 ml of a 250 g/l solution of nitric acid. Heat to 60C. Titrate with 0.05 M lead nitrate using 4-(2-pyridylazo)resorcinol monosodium salt as indicator.
1 ml of 0.05 M lead nitrate is equivalent to 10.30 mg of Na2MoO4.

Potassium Molybdate
CAS Number: 13446-49-6

Crystalline Potassium Molybdate is white powder represented by the chemical formula K2MoO4. It is anhydrous, but it is slightly deliquescent in air. The water solubility at 25°C (77°F) is 64.57% (wt. percent), 124 gm/100 cm3. It melts at 919°C.

Specification of Potassium Molybdate:
Assay (K2MoO4): 99.0
Insoluble Matter: <0.005
Ammonium (NH4): <0.001
Chloride (Cl): 0.005
Iron (Fe): <0.01
Heavy Metals (as Pb): 0.0005
Phosphate (PO4): 0.0005
Sulfate (SO4): 0.015

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