When zinc chloride is dissolved in water many complexes are formed. How many complexes are formed and what are they ? What is the complex which has the largest Ka?

Is ZnCl4 2- also present in ZnCl2 solution?

1 Answer
Nov 25, 2017

Answer:

Got a text book...?

Explanation:

We write...

#ZnCl_2(s) stackrel(H_2O)rarrZn^(2+) + 2Cl^(-)#

#Zn^(2+)# is likely present in solution as #[Zn(OH_2)_6]^(2+)#, a coordination complex if you like of #Zn^(2+)#; chloride ion might be solvated by #4-6# water molecues....we write #Zn^(2+)# or #ZnCl_2(aq)# as a shorthand.

In the presence of HIGH concentrations of halide ion....the #"tetrachlorozincate"# ion, i.e. #[ZnCl_4]^(2-)#, may be formed...In an aqueous solution of #ZnCl_2#, the dominant species in solution is #[Zn(OH_2)_6]^(2+)#, and aquated chloride ion....

I have no data to hand, but the metal complex would probably affect the #pH# of the solution....

#[Zn(OH_2)_6]^(2+) +H_2O(l) rightleftharpoons[Zn(OH)(OH_2)_5]^(+) +H_3O^+#

A solution of zinc ion would thus probably have a #pH<7#...