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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: geubrina on March 26, 2008, 04:21:33 AM

Title: NaOH + ZnSO4
Post by: geubrina on March 26, 2008, 04:21:33 AM
I want to buy some Zinc Powder or Zinc metal, but in my town, the zinc powder's price is more than USD 100 per kg. However, I found ZnSO4 at USD 1.2/kg.

Can I make the zinc powder by adding the ZnSO4 to NaOH?

ZnSO4 + 2NaOH ---> Zn(s) + Na2SO4 + H2O

Please guide me....
Title: Re: NaOH + ZnSO4
Post by: Arkcon on March 26, 2008, 06:59:09 AM
I don't believe NaOH has the reducing power to form free Zn.  Sodium is more electropositive than zinc, and will not exchange easily.  Certainly, nothing useful will happen in aqueous solution.  If you really want to make your own zinc, you might try roasting it to the oxide, and maybe reducing it to Zn with carbon, under say, borate salts as a flux.  I used to play with US pennies in that fashion, they are simply a thin plating of copper over zinc.  But you're not likely to save money with these machinations.  Zinc and other such reactive metals are usually produced electrolytically, from the melt, hence the price.
Title: Re: NaOH + ZnSO4
Post by: geubrina on March 28, 2008, 10:38:07 AM
I think I must correct it:

2NaOH + ZnSO4 --> Na2SO4 +ZnO + H2O.

Is this reaction possible?
Title: Re: NaOH + ZnSO4
Post by: AWK on March 28, 2008, 10:50:16 AM
Not exactly

ZnSO4 + 2 NaOH = Na2SO4 + Zn(OH)2

Zn(OH)2 when heated can form ZnO
Title: Re: NaOH + ZnSO4
Post by: netthubuon on January 09, 2010, 07:18:15 PM
geubrina said to obtain Zn metal. You say when heated Zn(OH)2 is obtained ZnO. How is not obtained Zn?
Title: Re: NaOH + ZnSO4
Post by: BluRay on January 10, 2010, 02:01:28 PM
geubrina said to obtain Zn metal. You say when heated Zn(OH)2 is obtained ZnO. How is not obtained Zn?
You have to reduce the oxide to get the metal. You can do it even with coal, probably  at a reasonable temperature (that is, not extremely high).

About the reaction between zinc sulfate and sodium hydroxide, it should not be used an excess of sodium hydroxide, or the zinc hydroxide will dissolve again after precipitation, forming hydroxy zincate ion Zn(OH)4-.
Title: Re: NaOH + ZnSO4
Post by: aieeee on January 13, 2010, 01:15:36 AM
i agree with blueray. the reaction is :
ZnSO4 + 2 NaOH = Na2SO4 + Zn(OH)2 (white ppt.) + H2

and when NaOH is in excess then soluble complex Zn(OH)4-( can also be written as ZnO22-+H2O) is obtained.

this is a misconception that anything like Zn or ZnO is obtainewd by heating Zn(OH)2 , as its a precipitate.
Title: Re: NaOH + ZnSO4
Post by: Borek on January 13, 2010, 02:56:23 AM
ZnSO4 + 2 NaOH = Na2SO4 + Zn(OH)2 (white ppt.) + H2

Have you tried to balance this reaction?