Devarda's alloy
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Devarda's alloy is an alloy of aluminium, copper and zinc used as a reducing agent in analytical chemistry for the determination of nitrates from a sample after their reduction to ammonia under alkaline conditions, method which has now largely been replaced by ion chromatography.
Contents
Composition
Devarda's alloy consists of aluminium (44% – 46%), copper (49% – 51%) and zinc (4% – 6%).
Properties
Devarda's alloy is a silvery-gray metallic alloy, odorless and insoluble in liquids. It melts between 490 to 560 °C and boils at 906 °C. It has a density of 5.79 g/cm3 at 20 °C and a bulk density of 2.08 g/cm3.[1]
Devarda's alloy will react with bases, such as sodium hydroxide to release hydrogen.
Availability
Devarda's alloy can be purchased from chemical suppliers and online.
Preparation
Devarda's alloy can be made by melting a mixture of aluminium, copper and zinc.
Projects
- Determine the concentration of nitrates from a sample
- Obtain ammonia from nitrates
Handling
Safety
Ingestion or inhalation of Devarda's alloy is harmful.
Finely powdered Devarda's alloy is flammable and should be handled with care.
Storage
Devarda's alloy should be stored in closed bottles, away from bases, acids and oxidizers.
Disposal
Devarda's alloy can be recycled by neutralizing it with an acid and then recovering copper and zinc via reduction. It can also be dumped in trash.
