What is Ammonium Hydroxide 29% ACS Grade?

Ammonium Hydroxide 29% ACS Grade is a clear, colorless, volatile alkaline liquid. It consists of ammonia gas dissolved in water, yielding a highly reactive solution with complete water miscibility. The ACS Grade designation indicates that this solution meets the strict purity standards set by the American Chemical Society, making it suitable for precise analytical and laboratory applications.

With a molecular weight of 35.05 and a boiling point of 37°C (98.6°F), this 29% concentration provides a potent source of alkalinity. Its high volatility means it readily releases ammonia vapor at room temperature, requiring careful handling and storage.

ACS Grade vs. Technical Grade

When selecting ammonium hydroxide, operators must choose between ACS Grade and Technical Grade based on application requirements. Ammonium Hydroxide 29% ACS Grade is refined for minimal impurities, ensuring reliable results in sensitive analytical procedures. In contrast, Ammonium Hydroxide 29% Technical Grade offers the same 29% concentration but is manufactured for bulk industrial processes where trace impurities do not impact the final product.

Both grades share the same CAS number (1336-21-6) and chemical formula (NH4OH), but slight variations in physical properties, such as boiling point, reflect the difference in purity levels.

Laboratory and Analytical Applications

In analytical chemistry, Ammonium Hydroxide 29% ACS Grade is an indispensable reagent. Its high purity ensures that trace metals and other contaminants do not interfere with sensitive assays. Primary laboratory uses include:

• Qualitative Inorganic Analysis: Used to precipitate metal hydroxides and identify specific cations.
• pH Adjustment: Acts as a precise alkaline buffer in titrations and chemical syntheses.
• Complexometric Titrations: Forms stable complex ions with transition metals, facilitating accurate concentration measurements.

Role in Water Treatment and pH Control

Ammonium hydroxide is widely utilized in municipal and industrial water treatment facilities. Its complete water miscibility allows for rapid integration into aqueous systems. Operators use it primarily to elevate the pH of acidic water streams, protecting pipes and infrastructure from corrosion. Additionally, in municipal water treatment, it is combined with chlorine to form chloramines, providing a stable, long-lasting residual disinfectant throughout the distribution network.

Metal Treatment and Surface Preparation

The metal finishing industry relies on ammonium hydroxide for surface preparation and cleaning. Its alkaline nature makes it highly effective at neutralizing residual acids from prior pickling or etching steps. It is also used in the formulation of specialized metal cleaners, where it helps remove organic residues and oxides without degrading the underlying metal substrate. For delicate electronic components, the ACS Grade ensures that no conductive impurities are left behind after the cleaning process.

Industrial Manufacturing and Synthesis

Beyond the laboratory, Ammonium Hydroxide 29% serves as a critical precursor in large-scale chemical manufacturing. It provides the nitrogen source necessary for synthesizing a variety of organic and inorganic compounds. Common industrial applications include the production of amines, specialized plastics, and agricultural fertilizers. The 29% concentration offers an efficient balance of reactivity and transportability for these high-volume processes.

Safe Handling and Storage Requirements

Because Ammonium Hydroxide 29% is a volatile alkaline liquid with a boiling point near human body temperature (37°C / 98.6°F), it presents specific handling challenges. It must be stored in a cool, dry, well-ventilated area, away from direct sunlight and heat sources. Containers must be kept tightly closed to prevent the escape of pungent ammonia vapors and the gradual loss of concentration.

Ammonium hydroxide is incompatible with strong acids, halogens, and certain metals. Always consult the product Safety Data Sheet (SDS) for specific personal protective equipment (PPE) requirements, hazard classifications, and spill response procedures.

Frequently Asked Questions