Caustic Soda Pellets
NaOH -- 40.00
DEFINITION
Content: 97.0 per cent to 100.5 per cent Sodium Hydroxide.
CHARACTERS
Appearance: White or almost white, crystalline masses, supplied as pellets,
sticks or slabs, deliquescent, readily absorbing carbon dioxide.
Solubility: Very soluble in water, freely soluble in ethanol (96 per cent).
IDENTIFICATION
A. pH minimum 11.0.
B. 2 ml of solution S gives reaction of sodium.
TESTS
Solution S: Carry out the procedure described below with caution. Dissolve
5.0 g in 12 ml of distilled water. Add 17 ml of hydrochloric acid R1, adjust to pH 7
with 1 M hydrochloric acid and dilute to 50 ml with distilled water.
Appearance of solution: The solution is clear and colourless.
Dissolve 1.0 g in 10 ml of water.
Carbonates: Maximum 2.0 per cent, calculated as Na2CO3 as determined in the
assay.
Chlorides: Maximum 50 ppm.
Sulphate: Maximum 50 ppm.
Iron: Maximum 10 ppm, determined on solution S.
Heavy metals: Maximum 20 ppm.
NaOH -- 40.00 -- 1310-73-2
Caustic Soda Pellets
Sodium Hydroxide contains not less than 95.0 percent and not more than 100.5 percent
of total alkali, calculated as NaOH, including not more than 3.0 percent of
Na2CO3.
Caution—Exercise great care in handling Sodium Hydroxide, as it rapidly destroys
tissues.
Identification: A solution (1 in 25) responds to the tests for Sodium.
Insoluble substances and organic matter: A solution (1 in 20) is complete,
clear, and colorless to slightly colored.
Potassium: Acidify 5 mL of a solution (1 in 20) with 6 N acetic acid, then
add 5 drops of sodium cobalt nitrite TS: no precipitate is formed.
Heavy metals: the limit is 0.003%.
Caustic Soda Pellets
NaOH Formula wt 40.00
INS: 524 CAS: [1310-73-2]
DESCRIPTION
Sodium Hydroxide occurs as white or nearly white pellets, flakes, sticks, fused
masses, or other forms. Upon exposure to air it readily absorbs carbon dioxide and
moisture. One gram dissolves in 1 mL of water. It is freely soluble in alcohol.
Function: pH control agent.
REQUIREMENTS
Identification: A 1:25 aqueous solution gives positive tests for Sodium.
Assay: Not less than 95.0% and not more than 100.5% of total alkali,
calculated as NaOH.
Arsenic: Not more than 3 mg/kg.
Carbonate: (as Na2CO3) Not more than 3.0%.
Insoluble Substances and Organic Matter: Passes test.
Lead: Not more than 2 mg/kg.
Mercury: Not more than 0.1 mg/kg.
NaOH
Formula Weight 40.00
CAS Number 1310-73-2
REQUIREMENTS
Assay: 97.0% NaOH min
Sodium Carbonate: 1.0% Na2CO3 max
MAXIMUM ALLOWABLE
Chloride (Cl): 0.005%
Nitrogen compounds (as N): 0.001%
Phosphate (PO4): 0.001%
Sulfate (SO4): 0.003%
Ammonium hydroxide precipitate: 0.02%
Heavy metals (as Ag): 0.002%
Iron (Fe): 0.001%
Mercury (Hg): 0.1 ppm
Nickel (Ni): 0.001%
Potassium (K): 0.02%
