ONLY this acid can dissolve GOLD. Selenic acid

[@Hydrazine1000]

I read the title of this video, and thought _"Hey, but aqua regia can dissolve gold!"_ ... and then it hit me: aqua regia is a _mixture_ of two acids, it's a compound chemical. It's not a (singular) acid. Ok, crisis averted, carry on!

[@kingnhonj954]

That's the exact thought I had also

[@menjolno]

no. aqua regia is nitrosyl chloride. It is not a acid because there is no hydrogen. It is a salt

[@davidmackenzie9701]

Aqua regia is a solution of nitrohydrochloric acid. The traditional solution is comprised of a 3:1 mixture of hydrochloric acid and nitric acid, respectively. It will oxidize over time to form toxic nitrosyl chloride, nitrogen dioxide and chlorine gases.

[@Hydrazine1000]

@@menjolno Uhmmm, there is nitrosyl chloride _present in_ aqua regia, due to a chemical balance (reversible reaction) between HCl and HNO3 on one side and H20 and NOCl on the other side of the equation. And since NOCl is gaseous, and some will outgas, it can be regarded as a decompostion product. Aqua regua is still (mostly) about 1 volume part nitric acid to 3 parts hydrochloric acid. (1:3 molar ratio to be more accurate.)

[@martyc2051]

i too was thinking aqua regia, but then realized that its a compound, and neither of the 2 acids can effectively dissolve gold on an independent basis (if im wong, i do stand to be corrected of course)

[@gefulltetaubenbrust2788]

Man selenium is such an underrated element. Just those blue flames are cool as hell, not even mentioning its awesome chemistry, just a shame most its compounds are toxic :(

[@ChemicalForce]

underrated like my channel 😂

[@chikianglim3632]

@ChemicalForce Nah that’s not true

[@thebogsofmordor7356]

​@@ChemicalForcethose of us that know, know. But yes, even after this long how you have only 150k subs blows my mind. You have the most beautiful chemistry on KZbin!

[@gefulltetaubenbrust2788]

@@ChemicalForce lol that's true

[@willgund779]

@@thebogsofmordor7356 I think most people just don't understand chemistry, and don't have the patience to appreciate it

[@skyethebi]

I really love when you show the synthesis of compounds in the video such as with nitrosyl perchlorate, PbCl4, Cl2O6, and any of the pyrophoric gases.

[@skyethebi]

It’s interesting that silane is generally created using a source of H+ and germane is created with a source of H-. Is that because it’s hard to get germanium in a negative oxidation state to begin with?

[@vornamenachname6300]

I've wanted to see the reaction with gold for years, but there was so much more cool stuff in this. Awesome video!

[@bedlaskybedla6361]

Nice video! You could try to dissolve elemental S, Se and Te in H2SeO4, they form the same coloured polycations like in H2SO4, but they are less stable in H2SeO4 due to its oxidizing properties (hot H2SeO4 oxidize them to IV oxidation state).

[@YunxiaoChu]

Cool

[@Tranarpnorra]

Amazing chemistry and excellent photography as always! My only real practical contact with Selenium is a Selenium rectifier. As an automation technician/electrician I've had a few of these go bad on me. The smell they give off when burned is almost puke inducing.

[@Progamezia]

dude, im telling you, these videos are so good, exotic and just overall insane. Keep it up. Thank you Felix for making these awesome videos and cultivating a love for chemistry within many.

[@therealtime-o]

As always, a great Video. Thank you for all your effort.

[@Lucinat0r]

You should do a video with the Slow Mo Guys, would love to see some of the extremely fast reactions at super slow mo. since they can do over a million+ fps it would produce amazing shots.

[@TooMuchMiddle]

Another fascinating and beautifully filmed lesson in chemistry. It is criminal that you don't have more subs.

[@filipstone2]

Holy! That was an incredible video. Thanks for the detailed documentation of the synthesis. All of those selenium compounds are terrifyingly toxic. I'd love to see your safety set up some time. Thanks for all the hard work!

[@prapanthebachelorette6803]

Yes, safety tips please 😊

[@PhantomKING113]

One of my favourite acids of all times, if not my favourite. Until now there was... one video about it on KZbin? PMC is a good channel, but so is this, and we actually get to see its famous reaction with gold! Great video! Edit: I think very concentrated, very hot sulfuric acid can also eat at gold, though very slowly.

[@mokouf3]

Piranha solution (sulfuric acid + hydrogen peroxide) can dissolve gold.

[@grebulocities8225]

@@mokouf3 Sreetips tried that, but essentially no gold dissolved even when strongly heated.

[@beefgoat80]

I work for a jeweler. I love how much chemistry goes into purifying recycled gold. The metals most "gold" jewelry is alloyed with is treated like slag. But it's all about creating a gold precipitate they can melt down and turn into more jewelry. It's crazy how much gold has been recycled. Some of the gold in your wedding band just might have come from some ring that was sold to a gold buyer, and, in turn, was sold to a jewelry manufacturer. My boss buys old jewelry all of the time. We remove all of the stones and send it off to a recycler. My boss then gets a cut of the gold extracted. Most gold you wear on your finger is old gold.

[@christopherleubner6633]

I'm pretty sure that gold is the most recycled metal. Literally recycled since it was plucked from rocks before the bronze age...

[@beefgoat80]

@@christopherleubner6633exactly. if it was easy to get gold out of the ground, there wouldn't be such a large industry focused solely on recycling gold. For every person wanting to buy a gold ring, there's someone looking to sell a gold ring. It's the circle of life. Lol

[@RedDeckRedemption]

​@@beefgoat80copper and tin were also extremely abundant on the surface. Your brass doorknob was a bronze sword 6000yrs ago lol

[@ZoonCrypticon]

Very interesting! Could you next time perform experiments with telluric acid ? And if you should have enough leisure time and a good standing with the secret service, perhaps polonium hydroxide ?

[@zajimavepokusy1666]

Wow, I'm so amazed. I never even heard of selenic acid. It was also pretty cool to see the the copper selenate that looked the same as copper sulphate. I think that by mixing the copper selenate with sodium hypochlorite you might get red selenium along with copper oxide. Aldough i'm not sure. I think this was one of your best videos, keep up with the great work ! Amaizing.

[@glarynth]

Amazing photography as always. It's nice to see these exotic substances up close and not die.

[@KomradZX1989]

Every video you make I always think, “wow this is the most beautiful chemistry video I’ve ever seen…” and then you make another video 😂❤ Love your work buddy! You rock!!!

[@brandonowens282]

7:24 awesome shot of the crystals converging! As an amateur hydro metallurgist, it's interesting to see yet another why to dissolve gold. What do you use to precipitate the gold back out of solution?

[@yahyae3416]

Sodium metabisulfite or iron 2 chloride

[@brandonowens282]

Thanks! Do you happen to know how to drop aluminum from a chloride solution? I was messing around with some e-waste using hydrochloric acid and hydrogen peroxide, I'd like to dispose of it in a ethical manner. I used aluminum to rapidly cement copper, now I'd like to get the aluminum out, neutralize the pH and dump the solution down the drain. Got any suggestions?

[@yahyae3416]

@@brandonowens282 In fact, it is not a problem to neutralize aluminum chloride with a base and pour it into the sewer. You can even throw the precipitated aluminum oxide onto the pavement.

[@juliofoolio2982]

Your deadpan delivery with the dramatic explosions hits me as deeply comedic. Thank you.

[@chikianglim3632]

Dude you are one of the best chemistry channels on this app. Only one working on such exotic reagents. Keep it up!🎉 (maybe a reaction of copper sulfate or copper selenate with different salts? e.g magnesium chloride? Maybe some metal salts have differing solubilities and color?)

[@TheBackyardChemist]

I die inside a little bit every time someone calls a website an app...

[@acetate6]

@@TheBackyardChemist Feel you

[@jimcoppa6946]

That was quite beautiful the way those sulentic acid crystals were formed good job

[@Luna-br3jb]

The macro shots this man produced are some of the most genuinely beautiful images I’ve seen in my life

[@Aut0mati0n]

When you hit the sodium with the second drop of the acid you could see the angular momentum for a second. Super cool.

[@Дмитрий_1981]

Most interesting experiences. Thank you. P.S. It’s a pity, on pause, the KZbin interface icons obscure the equations of chemical reactions, which I don’t always have time to read, as, for example, at minute 16:11

[@iankynaston-richards5239]

Tap on the screen again and the pause icon will go.

[@mark879]

Such beauty! The footage, the music, the crystals, the fly, wow! Amazing production value! I thank you for sharing and I thank the KZbin algorithm for bringing me here. Love these videos!

[@CatMowpurr]

Looks like a small wasp or ant, with the wasp waist, long antennae and 4 wings

[@umbrakinesis2011]

Incredible, after quite a few somewhat tame experiments, I was quite surprised when the test tube exploded from the white phosphorus -p4 is usually violent, but I wasn't expecting such a bang from so little. Awesome chemical, and a great presentation.

[@asmrlifereal]

Amazing Video. Thank you for the closed caption and segment titles!!!

[@kenbrady119]

Fantastic footage! Selenic acid has fascinated me since I was a kid. Any chance of moving on to tellurium?

[@anthonycabrera6318]

Awesome video like all you produce, can you use perchloric acid next and his reactions with diferrents elements🤔🤔

[@TheCubedPixel]

11:56 That random wasp deserves an Oscar

[@Bike36_]

Nice video! Can you record your cleanups just as NileRed does? I think it would be fun to watch some more exotic cleanups. It must be pretty challenging to clean up after using things like hydrazine and selenic acid. Also, instead of regular sugar, you should have tried using glucose because selenic acid is an oxidizing acid and glucose is a reducing sugar. I think it would have been interesting.

[@chikianglim3632]

Yesss!

[@DaftFader]

You saw the clean up in the video ... adding white phosphors and Hydrazine to the rest of the selenic acid. xD

[@Bike36_]

​@@DaftFaderYeah lol. The best way to clean stuff up is just blow it up, as we all know!

[@duncanwilkie179]

That was an action packed video. You invested a lot of time in preparing, testing, filming and editing the content. A huge thank you for your efforts. You have some sweet glassware and equipment.

[@among-us-99999]

I think molybdenum and niobium are under-appreciated elements

[@ЕвгенийДробышев-ц2т]

As always an impressive video!

[@lorenwilson8128]

HCN is technically an acid and dissolves gold. Hydrogen cyanide is used in most gold-mining operations to dissolve the gold out of the ground-up ore.

[@markfudger5267]

Used to be called Prussic acid.

[@YunxiaoChu]

Ehhh still needs oxygen to work

[@Marbslab]

Incredible video with all the close-ups and slow-mos.

[@user-SmashHit1234perfect]

Selenium is a chemical element with the symbol Se and atomic number 34. It is a metalloid (more rarely considered a nonmetal) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth).

[@navidahmed1]

Man! The production quality is through the roof!

[@petevenuti7355]

I'm surprised you didn't try and mix with permanganate‽ Also thinking that gold selenate could make some interesting red glass when melted in...

[@phillifighter1337]

The fact that no hydrogen is produced points to the gold being oxidized by the selenate and not the protons. Could you try to dissolve gold in sodium selenate?

[@canonicaltom]

Try contacting the slo-mo guys to see if they might be able to film some of the faster reactions at much higher framerates

[@kalebmaciver7117]

great video, I have really enjoyed the selenium chemistry you have shown so far. are you going to continue with some more selenium chemistry?

[@drmilkweed]

this video really showcases the beauty of pure chemistry. I've done my fair share of vacuum distillations and crystallizations and this really captured the sense of awe and wonder i felt the first time I did them in organic chemistry lab. thanks for the awesome content!

[@jtbmetaldesigns]

You made my day with slow motion selenium acid oxidation’s of other compounds. My life is more spectacular watching this!

[@pakey423]

Now make a Piranha solution with Selenic Acid instead of Sulfuric Acid......😉😁

[@ChemicalForce]

😂 haha this idea has been in my head for a long time! I've already tried dissolving crystalline selenic acid in 60% hydrogen peroxide (the highest concentration of commercially available hydrogen peroxide) on cooling. I think I'll take on this video but first I need to finish the material on WF6.

[@YunxiaoChu]

Hmm.

[@ARSZLB]

i swear i could watch seed recrystallizations all day. just so beautiful

[@HurricaneOK1]

Very relieved the fly turned around. What a plot twist, having a totally new character just appear like that.

[@cake4919]

I wonder if HCN can dissolve gold on it's own, it might need to be HCN in water though so the gold cyanide dissolves which would push the reaction forward.

[@tiagoferreira086]

Your videos are always awesome! Great content and editing skills!👍

[@tanmoysarkar5848]

Recently found your channel and now I can't stop watching!

[@Ang3lUki]

Who does the music in your videos? Are you friends with Ennio Morricone? The music always is perfectly inline with the action on screen, it's amazing! The dissonant strings and piano notes when the fly showed up were so spot on!

[@thesentientneuron6550]

Looking at the reaction of selenic acid dissolving gold, it seems to work because it's an oxidizing acid much like how aqua regia or chlorine water can dissolve gold. Makes me wonder if concentrated (98%) boiling sulphur acid can also dissolve gold...?

[@grebulocities8225]

It can't, at least not appreciably. Sulfate doesn't seem to complex with gold as well as selenate does.

[@derktewinkel]

Very nice video! I really liked the preparatory part with the distillation!

[@diablominero]

As I recall, strontium sulfate precipitates much slower than barium sulfate (like a 10-second delay between mixing strontium nitrate with sodium sulfate and seeing precipitate). Does strontium selenate also precipitate with a delay, or is it instantaneous like barium selenate and barium sulfate?

[@terribleterrier1685]

How do you not have over 500k subs by now? Your videos are freaking great. I blame KZbin.

[@DavidFMayerPhD]

What about telluric acid?

[@Ang3lUki]

The hydrazine reaction blew my mind, I wonder what's going on? Is the selenium being completely reduced and heated so fast that it ignites on contact with air as soon as it forms?

[@ajofmars2579]

I have a question; can this acid dissolve any other noble metals that are generally recognized as very non reactive, like Platinum or Iridium? I just googled about dissolving Iridium, and someone says that Iridium can be dissolved by molten salts like NaCl or NaCN, but not Selenic acid. I think this would be a very interesting video idea!

[@DavidePatti-x3l]

wow! i haven’t any words! i’ll follow your channel. i like the way you make video and also the particular reaction you do.

[@jpolowin0]

I'm trying to figure out what reaction might work between perchloric acid and gold. If gold chlorate exists, that would be a possible product, but the references that I'm finding for it don't look very reliable. If you're needing to get the perchlorate down to chloride, you'd need to get rid of more oxygen.

[@christopherleubner6633]

The reaction is from the decomposition of perchlorate to chlorine dioxide water and singlet oxygen. This quickly reacts to form monoatomic chlorine and oxygen. This then attacks the gold forming a complex that yields gold chloride oxygen and water. Perchloric acid is mighty unstable stuff.

[@xXthadillacXx]

This footage is amazing, man. Great job

[@OsmioIridio-og8cn]

Great contribution to our understanding of Selenium chemistry

[@chir0pter]

that bee finding your selenic sugar cube and almost taking a drink, like finding an oasis in the desert but it's toxic to drink

[@stick-Iink]

11:34 fly moment

[@ellisoneves]

Very impressive video! Congrats

[@VendettaProspecting]

AU is a fantastic element

[@fukpoeslaw3613]

​@AuschwitzSoccerRef.Who are you and who stole your gold?

[@SuperAngelofglory]

As far as I know, perchloric acid does not dissolve gold. However, Wikipedia claims dichlorine hexoide does react with gold, releasing chloryl auroperchlorate ClO2[Au(ClO4)4 and chlorine.

[@mobilemarshall]

really nice footage, thanks for making these videos

[@hitoall123]

the crystalization of selenic acid, pure magic, thank you

[@pyr0duck676]

Once I finish grad school and get a nice paying job next year, I'm definitely going to become a Patreon! Thanks for your videos!

[@SmokeyPyro]

I wonder how violent the last reaction could be if there was a way to instantly mix it homogenous, so all molecules could properly react with eachother Since those last 2 reactions we're so damn violent, im very curious

[@joaquinfernandez8928]

BEAUTIFUL SHOOTAGE! 👍👍

[@brandynamite3022]

I heard that phenolpathlein turns orange in concentrated sulfuric acid, I wonder if it will do something similar in selenic acid

[@tracybowling1156]

I ❤️ your videos, Feliks! Thank you!

[@Yamazaki339]

Amazing video! As usual!

[@heyihavenoclue7541]

Well maybe the mass would help distinguish between CuSO4 & CuSeO4 ( quantitatively) ? I am not sure though, but that was my first thought. Awesome video!

[@thesentientneuron6550]

Or maybe a test of its oxidizing properties, say by the addition of a thiosulphate salt or sulphur powder, perhaps?

[@heyihavenoclue7541]

@@thesentientneuron6550 I like the L pfp and yes perhaps

[@thesentientneuron6550]

@@heyihavenoclue7541 Thank you! You have an adorable pfp too.

[@Martin-wj6um]

Biurethic reaction, maybe?

[@pablog.3906]

Beautifully made!

[@frvl]

By the way, when gold is dissolved, a mixture of Au2O(SeO3)2, Au2(SeO3)2(Se2O5) and Au2(SeO3)2(SeO4) is formed.

[@Esterified80]

16:55 Forbidden salmon slices 17:35, 17:50 Forbidden omelette

[@bunsenn5064]

It would be interesting to explore the hexafluoropnictogen acids, like hexafluorophosphoric acid, hexafluoroarsenic acid, etc. they have some pretty cool properties.

[@skyethebi]

8:45 for an acid (or mixture) to dissolve gold it has to be able to oxidize it right? That’s why nitric acid is required in aqua regia; however nitric on its own can’t dissolve gold. Is that because gold nitrate is unstable? I know that aqua regia forms chloroauric acid when it dissolves gold which makes me wonder if the gold needs to be coordinated by something (such as chloride ions) to remain dissolved in solution. If that’s the case I’m wondering what’s coordinating the gold when selenic acid dissolves it. Furthermore, just out of curiosity can you dissolve gold with other hydrohalic acids mixed with nitric acid? It might be cool to do a video about trying to dissolve gold in various acids and combinations or even other things like ICl.

[@Ang3lUki]

One of the biggest takeaways I think could be had from all of your videos, is that you cannot react faster than reactions. Every time you're interacting with a reaction and it explodes, the slow-mo shot always shows you reacting long after chemicals have splashed everywhere and the reaction has gotten out of hand. It's a good thing your safety standards are so good, and that really drives the point home.

[@georgejanzen774]

My man has a death wish, splashing around all that hydrazine...

[@PaulSteMarie]

Ok, so where the heck does the hydrogen go when dissolving gold? Does it reduce some of the selenic acid to selenous acid?

[@Jeff-jr4xw]

Great editing with the music!

[@DriftersDiesel]

A master of art and science. These videos are incredible.

[@amitygames9318]

Work of genius. Holy smokes, how comes the reaction with P is so violent ?

[@LyingOstrich]

Phosphorus is highly reactive.

[@Scou73r]

I'd love to see you collaborate with a super slow framerate channel for very fast reactions. Maybe slo-mo guys?

[@marlberg2963]

Selenic acid is not the only acid that dissolves gold. Sulphuric and Nitric acid in combination called Aqua Regia can also dissolve gold

[@Bloated_Tony_Danza]

If gold dissolves in selenic acid, and selenium is related to tellurium...is that why gold telluride is one of the only naturally occurring gold compounds?

[@abrasivepaste]

Amazing visuals! What filming equipment do you use? Whatever lens you're using is incredibly sharp

[@dmsnch]

I wonder how gold selenate would work as a toner for silver photographic prints? Gold chloride and sodium selenite are used separately, but maybe a selenate is too oxidising.

[@petevenuti7355]

... You got me thinking, exactly under what conditions is sulfuric acid reduced to sulphur? Could a lifeform do it in a photosynthesis like process?

[@claytonbenignus4688]

Because Gold and Tellurium occur naturally in the mineral Calaverite, I would be curious about trying to dissolve Gold in Telluric Acid.

[@accipiterignitus5123]

Man this channel is f underrated

[@ГеоргийХромов-м3щ]

Very impressive chemistry of selenium! It would be pretty interesting to look at complex substances and organic compounds of this element.

[@crabsaresilly8317]

You leave on 2 table lamps with 2 different kind of bulbs. You wait to see which type of bulb burns out first after a while and how long it takes for each one. Would you consider this example to be a scientific experiment ? ...

[@petevenuti7355]

Isn't Selenic acid good for a certain "gentle" oxidations and organic chemistry?

[@VinsCool]

13:00 that looks like a delicious mug cake that was just slightly overbaked, yum!

[@sqookylol2218]

good background music choices idk how but it just is amazing and fits what you do

[@evilotis01]

hey @ChemicalForce, do you have any thoughts on the reason for the differences between H2SO4 and H2SeO4? e.g. why does the latter take longer to carbonize sugar? is it something to do with selenium having a higher atomic weight...? but why would that make a difference?

[@thesentientneuron6550]

FYI What I say below is just speculation: I think possibilities might be the physical size of the molecule being larger, hindering reactions (?) and/or the lower electronegativity of selenium compared sulphur making it a weaker acid playing a role (?)

[@TheBackyardChemist]

Look at the standard redox potentials for selenium and sulfur compounds. SeO4²⁻ is a much more potent oxidizer.

[@vapenation7061]

@@TheBackyardChemist wouldn't that make it react faster than sulfuric acid?

[@nitrgnlab9400]

@@vapenation7061 it's also a less stronger acid than H2SO4 (so the dehydration reaction proceeds slower)

[@christopherleubner6633]

Yup the bigger Se atom makes it less likely to form the coordination with the water molecules that causes the dehydration, it still has an extreme affinity for water so it will carbonize the sugar, just slower.