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Aqueous

Definition

• Aqueous refers to a solution in water.

  A more exact definition is a solution in which the solute (the substance dissolved) initially is a liquid or a solid and the solvent is water.

Additional Info

Aqueous solutions fall into three general categories based on how well they conduct electricity:
• Strong electrolytes when dissolved in water dissociate completely into ions and conduct electricity. For example, sodium chloride, NaCl, dissociates into Na⁺ and Cl- ions in water. Other examples of strong electrolytes are nitric acid (HNO₃) and sodium hydroxide (NaOH).

• Weak electrolytes when dissolved in water do not dissociate to any large extent and therefore do not conduct electricity very well. Examples include ammonia (NH₃) and acetic acid (CH₃COOH).

• Non-electrolytes do not dissociate to ions in water and do not conduct electricity. Examples include sugar (sucrose = C₁₂H₂₂O₁₁), ethanol (CH₃CH₂OH) and methanol (CH₃OH).

Caution: do not interpret this language to suggest that it is safe to work with electricity around water! Electricity and water never mix safely.

MSDS Relevance The term aqueous may appear on an MSDS in terms of a special instruction (such as first aid procedures), a particular chemical property, or a chemical incompatibility. Aqueous solutions are not usually flammable, but may be able to carry toxic materials into your body through skin contact or ingestion. Be careful with terminology. A solution of ammonia gas (NH3) in water is often called ammonium hydroxide, NH4OH, ammonia water, or simply ammonia. Do not confuse this aqueous solution with ammonia gas (anhydrous ammonia)! Further Reading Aqueous Solutions at Tanner's General Chemistry. Reactions in Water or Aqueous Solution at About.com. Aqueous Solution at Wikipedia.

Emergency eyewash bottles (available at Safety Emporium) contain aqueous saline solution.

See also: concentration, electrolyte, solubility, solution, solvent, water reactive.

Additional definitions from Google and OneLook.

Disclaimer: The information contained herein is believed to be true and accurate, however ILPI makes no guarantees concerning the veracity of any statement. Use of any information on this page is at the reader's own risk. ILPI strongly encourages the reader to consult the appropriate local, state and federal agencies concerning the matters discussed herein.