Sciencemadness Discussion Board

ZnCl2 from ZnO?

GreenD - 6-3-2012 at 08:49

Hello!

It would seem that ZnCl could be made from ZnO and HCl. The other product being water.

Has anyone carried this out? How concentrated does the HCl have to be? I have 1N (damn bio people!) HCl with some ZnO. I have read that heat isn't necessary as the ZnCl will spontaneously form - but removal of water should help.

Any tips on this simple reaction?

Adas - 6-3-2012 at 08:51

You can use any concentration. Be sure to react all ZnO and then evaporate water. How simple.

GreenD - 6-3-2012 at 08:55

Yay! This is my first chemical reaction. How neat :D

And - it should be easy to gauge. ZnCl2 is soluble in water, while ZnO is not. Oh what a wonderful reaction.

Nicodem - 6-3-2012 at 09:25

Quote: Originally posted by Adas  
You can use any concentration. Be sure to react all ZnO and then evaporate water. How simple.

Please, provide the reference. If it would be so simple to prepare zinc chloride, I don't see why researchers developed so many much more complicated methods to prepare it.
Quote: Originally posted by GreenD  
ZnCl2 is soluble in water, while ZnO is not.

Not only it dissolves in water, it also decomposes. It is not trivial to regenerate pure enough ZnCl2 from its aqueous solution.

simba - 6-3-2012 at 09:25

You can always buy muriatic acid (over 30% HCl) at the hardware store.

Endimion17 - 6-3-2012 at 10:44

You'll end up with zinc oxychloride. If you want zinc chloride, be prepared for messing with chlorine, unless you can buy the salt.

GreenD - 6-3-2012 at 11:06

So... I'm not going to get ZnCl2 from ZnO and HCl?

Can anyone link me to a ZnCl2 prep? I'm not very good at finding basic info- I always end up with the 2010 or 2009 papers.

Looks like (thanks AJKOER) adding KCl to the aqueous solution will cause the Zn-hypochlorite to give ZnCl and KClO3

[Edited on 6-3-2012 by GreenD]

LanthanumK - 6-3-2012 at 11:23

Zinc chloride is deliquescent. Prevention of decomposition when heated could be done by evaporating it from an HCl solution. Zinc sulfate is better for use as a primary zinc salt.

Endimion17 - 6-3-2012 at 11:39

Quote: Originally posted by GreenD  
So... I'm not going to get ZnCl2 from ZnO and HCl?

Can anyone link me to a ZnCl2 prep? I'm not very good at finding basic info- I always end up with the 2010 or 2009 papers.

Looks like (thanks AJKOER) adding KCl to the aqueous solution will cause the Zn-hypochlorite to give ZnCl and KClO3

[Edited on 6-3-2012 by GreenD]


At best you can get a deliquescent slush of hydrated salt, which is not actual zinc chloride.
Anhydrous zinc chloride is prepared by synthesizing it from the elements, which, in homemade conditions, usually ends up with slight chlorine poisoning.

GreenD - 6-3-2012 at 11:41

Damnit. ok. Internet shopping here i come.

Vikascoder - 13-3-2012 at 08:00

Zinc oxide is amphoteric so it will make zinc chloride with hydrochloric acid.

Nicodem - 13-3-2012 at 08:20

Vikascoder, please do not double-post replies. I have better things to do than the cleaning job. If you double-post by mistake make sure you delete the repeated post by using the "Edit | Delete this post" function. Make sure you read the forum's posting guidelines.
Quote: Originally posted by Vikascoder  
Zinc oxide is amphoteric so it will make zinc chloride with hydrochloric acid.

It is highly advised to read the entire thread before posting a reply (especially if it is as short as this one!). Also in general, it would help you immensely if you would do any reading at all.
It was already explained that dissolving zinc oxide (or zinc) in hydrochloric acid does not give zinc chloride. The only thing you get is an aqueous solution of hydrated (decomposed) zinc chloride. Zinc chloride hydrolyzes immediately in contact with water, hence it can not be easily regenerated from aqueous solutions (there are ways to do this, but nothing trivial: UTFSE for more info).

GreenD - 13-3-2012 at 08:33

For the record I put ZnO in 1N HCl (excess). Let stir for one hour - no noticeable difference.

Heated and stirred for 3 hours - no noticeable difference.

LanthanumK - 14-3-2012 at 08:13

The oxide could be calcined and therefore resistant to acid attack.

AirCowPeaCock - 14-3-2012 at 15:59

GreenD did the zinc oxide "dissolve"?