Question

A compound has the formula `PtCl_4*2KCl`...?

From electrical conductance tests of an aqueous solution of the compound, you find that three ions per formula unit are present, and you also notice that addition of `AgNO_3` does not cause a precipitate.

a) Give the formula for this compound that shows the complex ion present.

b) Explain your findings.

c) Name this compound.

Any help would be appreciated.

Answer 1

The complex is likely `"potassium hexachloroplatinate"`, i.e. `K_2[PtCl_6]`

Explanation:

Because no precipitate is observed with `Ag^+`, there is no free halide ion present, and so all the halides are bound to platinum metal. And thus `K_2[PtCl_6]`, a `"platinum IV+"` species, is likely. In solution it would give 3 equiv of ions: `2xxK^(+) + [PtCl_6]^(2-)`, which is consistent with the conductance measurements.

What is the likely structure of the platinum complex?