Zinc Chloride

[Ed Mc Dade]

I reacted 1.3 grams of Zinc with hydrochloric Acid. The hydrogen gas
bubbled off. Since I made ZnCl2 with 0.02 moles of Zinc, the zinc chloride
would contain 0.04 moles of chloride. This accounts for 2.7 grams of zinc
chloride. When I dried the solution to a dry powder on a hot plate there
was 12.6 grams. If I assume that there was no water left, then is all of
the excess weight -- 9.9 grams HCl?

ed mc dade

[Dr. Gennaro J. Gama]

Unhappily, if your calculations are correct, your solid is not dry. two
things may have happened:
1) ZnCl2 is known to be highly hygroscopic, in fact it is so hygroscopic it
is deliquescent. Your solid is not dry at all, since it is very difficult to
dry deliquescent compounds. ZnCl2 is normally sold as ZnCl2 .nH2O (n= 2, 3,
or 4). Normally the technique to detrimine if a given solid is dry is "heat
to constant weight". Use of vaccum may be necessary in some cases.
2) A complex material H2ZnCl4 may have formed. I DO NOT think it is likely
to have happened. I would stick to 1) till the day I die, but if this second
option took place (this material is thermolabile), that would indicate the
incorporation of 2 moles of HCl. Anyway, even if this happened, not all of
the sample would be of H2ZnCl4. Most would be ZnCl2.

What I think you have is probably ZnCl2.n H2O (a hydrate).

Ed Mc Dade <ejm...@email.msn.com> wrote in message
news:eg6Bn$Sp#GA.254@cpmsnbbsa03...

[Dr. Gennaro J. Gama]

one thing to take into account:
you will have 0.02 moles of ZnCl2 at the endo of the process, or 0.02moles
of ZnCl2.nH2O

[Alan Pemberton]

No.
HCl is a gas.
Hydrochloric acid is a solution of HCl gas in water.
If you dried it completely there is no weight left accountable by HCl.

Ed Mc Dade wrote in message ...

[Dr. Arthur C. Sucsy]

Mr. McDade,

The atomic weight of zinc (Zn) is 65.4. The formula weight of zinc
chloride (Zn Cl2) is 136.3.
Reacting 1.3 grams of zinc with hydrochloric acid will give 1.3 x 136.3
/ 65.4 or 2.7 g of zinc chloride.
Possible explanations for the extra 9.9 g of weight are 1.) incorrect
weighing of the initial zinc and/or the final zinc chloride, 2.)
insufficient drying of the zinc chloride (zinc chloride is deliquescent and
will pick up an appreciable amount of water from moist room air if left
exposed), 3.) the excess hydrochloric acid could have reacted with the
container, if the container were a reactive material such as aluminum (glass
or porcelain crucible are non-reactive).

ACS

Alan Pemberton wrote in message <7iabm0$uei$1...@news7.svr.pol.co.uk>...

[suman...@gmail.com]

Zinc Chloride (ZnCl2) is manufactured by us in best quality in High purity Grade, Battery Grade, Technical Grade and Commercial Grade.

All these are available in Solid, Powder and Liquid (Solution) form. The purity and impurity level can be adjusted according to the customer requirement.

For more information ->: http://www.galvanizingchemicals.com/products/zinc_chloride.html