Editing Ammonia (section)

=== Laboratory ===
[[File:Ammonia solution (25-28%).jpg|thumb|155px|A standard laboratory solution of 28% ammonia]]
The hazards of ammonia solutions depend on the concentration: 'dilute' ammonia solutions are usually 5–10% by weight (<&nbsp;5.62&nbsp;mol/L); 'concentrated' solutions are usually prepared at >25% by weight. A 25% (by weight) solution has a density of 0.907&nbsp;g/cm<sup>3</sup>, and a solution that has a lower density will be more concentrated. The [[Directive 67/548/EEC|European Union classification]] of ammonia solutions is given in the table.

<!-- EU Index no. 007-001-01-2 -->
{| class="wikitable"
|-
! [[Concentration]]<br />by weight (w/w)
! [[Molarity]]
! [[Concentration]]<br />mass/volume (w/v)
! [[GHS pictograms]]
! [[H-phrases]]
|-
| 5–10%
| 2.87–5.62&nbsp;mol/L
| 48.9–95.7&nbsp;g/L
| {{GHS07}}
| {{H-phrases|314}}
|-
| 10–25%
| 5.62–13.29&nbsp;mol/L
| 95.7–226.3&nbsp;g/L
| {{GHS05}}{{GHS07}}
| {{H-phrases|314|335|400}}
|-
| >25%
| >13.29&nbsp;mol/L
| >226.3&nbsp;g/L
| {{GHS05}}{{GHS07}}{{GHS09}}
| {{H-phrases|314|335|400|411}}
|}

The ammonia vapour from concentrated ammonia solutions is severely irritating to the eyes and the [[respiratory tract]], and experts warn that these solutions only be handled in a [[fume hood]]. Saturated ('0.880'–see ''{{slink|#Properties}}'') solutions can develop a significant pressure inside a closed bottle in warm weather, and experts also warn that the bottle be opened with care. This is not usually a problem for 25% ('0.900') solutions.

Experts warn that ammonia solutions not be mixed with [[halogen]]s, as toxic and/or explosive products are formed. Experts also warn that prolonged contact of ammonia solutions with [[silver]], [[mercury (element)|mercury]] or [[iodide]] salts can also lead to explosive products: such mixtures are often formed in [[qualitative inorganic analysis]], and that it needs to be lightly acidified but not concentrated (<6%&nbsp;w/v) before disposal once the test is completed.