Nitrosyl Chloride: Aqua Regia’s Main Component

Nitrosyl Chloride is a yellow gas that is commonly encountered as a component of aqua regia, a mixture of 3 parts concentrated hydrochloric acid and 1 part of concentrated nitric acid. It is a strong electrophile and oxidizing agent.
Aqua regia (HNO3 + HCl) is well-known for its ability to dissolve gold. It's able to do this because it contains nitrosyl chloride - NOCl.
In this video I synthesized Nitrosyl chloride and demonstrated its reaction with gold!

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0:00 - Formation of aqua regia (mixing nitric acid with hydrochloric acid)
0:35 - Synthesis of pure nitrosyl chloride
3:42 - NOCl Hydrolysis
4:05 - Chlorine vapors and acetylene
4:23 - Nitrosyl chloride and acetylene
4:37 - Burning magnesium in an nitrosyl chloride atmosphere
5:12 - Reaction with potassium iodide
5:42 - Reaction with Hydrogen sulfide
6:16 - Reaction with gold
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[chemistryofquestionablequa]

Always the best reactions with exotic reagents!

[WilcoOelen]

As always, beautifully filmed and stunning reactions. The almost disappearing gold foil is easy to understand. Gold foil is extremely thin and such a large piece of foil is only a few milligrams of gold. If this reacts to something else and the resulting compound is compacted into a small volume, then nearly nothing is left. I think that the yellow liquid looking stuff, adhering to the glass is a concentrated solution of HAuCl4. The evaporating cold ONCl leads to condensation of some water. Due to hydrolysis, this leads to formation of a mix of HNO3, HCl, ONCl and water, which dissolves the gold. The presence of the chloride makes oxidation of gold much easier, because it then can form a stable complex AuCl4(-). After evaporation of all ONCl, a strongly acidic concentrated solution of HAuCl4 remains behind.

[Atmix]

If I were to guess what happened to the gold foil, I'd suggest it dissolves itself via a nitrosonium intermediate:
4NOCl + Au -> [NO][AuCl4] + 3NO
[NO][AuCl4] + H2O -> HNO2 + H[AuCl4]
2HNO2 -> NO2 + NO + H2O (-> dissolves chloroauric acid to form the yellow droplets in your petri dish)

[stinooke]

As I understand it, NOCl is not the reason why aqua regia dissolves noble metals. It is simply an intermediate in its decomposition. The oxidizing ability of HNO3 combined with the coordinating ability of Cl- itself suffices to oxidize gold.

[marcspeer]

Vielen Dank für den lehrreichen Inhalt. Bitte weitermachen!

[belacickekl]

You should react Nitrosyl Chloride with Sodium Azide to produce Nitrosyl Azide!

[spiderdude]

Let’s dissolve gold, but…aqueous solutions are cringe.

[blattgruener]

The shots of the gold foil disappearing are crazy👍

[sulaimanabdullah]

thank you for another wonderful video
showing and explaining experiments that as a hobbyist I can not do is so useful to me.
your video presentations are a work of art.

[thetechfury]

Thats really cool. I like the chemical reactions with the other metals.

[Scoochie]

Borat meets chemistry. And I thought I was near the end of YouTube. Thank you.

[KomradZX]

This is THE BEST chemistry channel on YouTube, bar none. Nile Red has nothing on you 😂

[LimitedState]

The waxy yellow residue is likely polymerization of gold chloride complexes with by-products from the decomposition of NOCl. The exact nature of this residue could depend on moisture content, temperature, the stoichiometry of NOCl relative to gold purity, and even the degree of decomposition or sublimation of the NOCl. <3 love the content!

[Edge]

Great video as always thank you for sharing!

[AnonymosAnthropos]

Great footages and great explanations! Thank you !

[prevarication]

i have no idea what I am watching, but it is pretty damn cool.

[FMo-zt]

Very nice interactions that I have not seen even in graduate studies...but I do not know why I do not receive notifications

[RosannaPatruno]

What happens if you try to dissolve gold in a mix of nitric acid and HF ? I think it’s worth try it.

[empmachine]

Amazing work as always!!
I bet you could sidestep the condensation issues by having a camera submerged in room temperature water. then you could just dunk the thing and record away..
Maybe there's a probescope that can go underwater (and isn't the cost of a small motorcycle).

[InternetFiend]

Hey chemical force, Great Video!
I was wondering if halogen azides are really that unstable, I have read on wiki that iodine azide is relatively more stable than other halogen azides.