sludge bomb

fyeahuniverse:

image by Flickr/Cyberchemist

The Tollen’s Reagent is used to determine whether a solution contains an aldehyde or a ketone.

Dilute sodium hydroxide is added to aqueous silver nitrate, this gives silver oxide, sodium nitrate and water.

2 AgNO₃ (aq) + 2 NaOH (aq) → Ag₂O (s) + 2 NaNO₃ (aq) + H₂O (l)

Then, aqueous ammonia is added to the solution until it goes clear. This is due to the now silver ions existing as [Ag(NH₃)₂]⁺ complexes.

Ag₂O (s) + 4 NH₃ (aq) + 2 NaNO₃ (aq) + H₂O (l) → 2 Ag(NH₃)₂NO₃(aq) + 2 NaOH (aq)

The silver precipitates out onto the inside of the container, giving the notable silver mirror as seen above.

it’s funny how i’ve used this in high school but we weren’t allowed to use it in college when we actually needed to differentiate between aldehydes and ketones

(via hydrides)