Give the chemical formula that corresponds to each of the following compounds: (a) sodium tetrahydroxozincate(ii) (b) dichlorobis(ethylenediamine)cobalt( iii) nitrate (c) triaquabromoplatinum(ii) chloride (d) tetra-amminedinitroplatinum(iv) bromide

a. Na₂[Zn(OH)₄]

b. [Co(Cl)₂(en)₂]NO₃

c. [Pt(H₂O)₃Br]Cl

d. [Pt(NH₃)₃(NO₂)₂]Br₂

Explanation:

(a) Sodium tetrahydroxozincate(II)

Zincate(II) indicates the metal is Zn²⁺, tetrahydroxo are 4OH⁻, that is

[Zn(OH)₄]²⁻. As the molecule is a neutral salt of sodium:

Na₂[Zn(OH)₄]

(b) Dichlorobis(ethylenediamine)cobalt(III) nitrate

The metal is Co³⁺, bis(ethylenediamine) are (en)₂ and dichloro are 2 Cl⁻, that is:

[CoCl₂(en)]⁺

The counterion is NO₃⁻, that is:

[CoCl₂(en)₂]NO₃

(c) Triaquabromoplatinum(II) chloride

The metal is Pt²⁺, ligands are 3 H₂O and 1 Br⁻, that is:

[Pt(H₂O)₃Br]⁺

The counterion is Cl⁻:

[Pt(H₂O)₃Br]Cl

(d) Tetra-amminedinitroplatinum(IV) bromide

The metal is Pt⁴⁺, ligands are 2 NO₂⁻ anf 3 NH₃, that is:

[Pt(NH₃)₃(NO₂)₂]²⁺

As counterion is Br⁻ you need 2 Br⁻ for the neutral salt, that is:

[Pt(NH₃)₃(NO₂)₂]Br₂

I hope it helps!