(a moe' nee um kar' bo nate).
Carbonic acid, monoammonium salt mixture with ammonium carbamate;
Monoammonium carbonate mixture with ammonium carbamate [8000-73-5].
Ammonium Carbonate consists of ammonium bicarbonate (NH4HCO3) and ammonium carbamate (NH2COONH4) in varying proportions. It yields NLT 30.0% and NMT 34.0% of ammonia (NH3).
• A. When heated, it is volatilized without charring, and the vapor is alkaline to moistened litmus paper. A solution (1 in 20) effervesces with acids.
Sample solution: Place 10 mL of water in a weighing bottle, tare the bottle and its contents, add 2 g of Ammonium Carbonate, and weigh.
(See Titrimetry 541.)
Mode: Residual titration
Titrant: 1 N sulfuric acid VS
Back-titrant: 1 N sodium hydroxide VS
Blank: 50.0 mL of 1 N sulfuric acid VS, accurately measured
Endpoint detection: Colorimetric
Analysis: Transfer the Sample solution to a 250-mL flask, add 50.0 mL of 1 N sulfuric acid VS, and when the solution has been effected, add methyl orange TS. Titrate the excess acid with 1 N sodium hydroxide VS. Perform a blank determination. Calculate the percentage of ammonia (NH3) in the sample taken.
Result = [(B V) × N × F × 100]/W
Acceptance criteria: 30.0%34.0%
• Residue on Ignition 281: NMT 0.1%
• Chloride and Sulfate, Chloride 221: A 2.0-g portion shows no more chloride than corresponds to 0.10 mL of 0.020 N hydrochloric acid (0.0035%).
• Chloride and Sulfate, Sulfate 221: A 2.0-g portion shows no more sulfate than corresponds to 0.10 mL of 0.020 N sulfuric acid (0.005%).
• Heavy Metals, Method I 231
Test preparation: Reduce to a coarse powder, and volatilize 2 g on a steam bath. Add 1 mL of 3 N hydrochloric acid, and evaporate to dryness. Dissolve the residue in 2 mL of 1 N acetic acid, and add water to make 25 mL.
Acceptance criteria: NMT 10 ppm
• Packaging and Storage: Preserve in tight, light-resistant containers, and store at a temperature not above 30.