23. Chemistry of the Nonmetals

BF₃ reacts with F^- to give BF₄^-, but AlF₃ reacts with F^- to give AlF₆^3-. Explain.

Describe the molecular geometry of:

(b) AsH3

We've said that the +1 oxidation state is uncommon for indium but is the most stable state for thallium. Verify this statement by calculating E ° and ΔG ° (in kilojoules) for the disproportionation reaction

3 M+1aq2S M3+1aq2 + 2 M1s2 M = In or Tl

Is disproportionation a spontaneous reaction for In+ and/orTl+? Standard reduction potentials for the relevant halfreactions are

In3+1aq2 + 2 e- S In+1aq2 E° = -0.44 V

In+1aq2 + e- S In1s2 E° = -0.14 V

Tl3+1aq2 + 2 e- S Tl+1aq2 E° = +1.25 V

Tl+1aq2 + e- S Tl1s2 E° = -0.34 V

Identify the group 3A element that best fits each of the following descriptions.

(c) Is extremely toxic

List three ways in which the properties of boron differ from those of the other group 3A elements.

Explain why the properties of boron differ so markedly from the properties of the other group 3A elements.