Question

While selenic acid has the formula H₂SeO₄ and thus is directly related to sulfuric acid, telluric acid is best visualized as H₆TeO₆ or Te(OH)₆?

1. What is the oxidation state of tellurium in Te(OH)₆?
2. Despite its structural differences with sulfuric and selenic acid, telluric acid is a diprotic acid with pKa₁ = 7.68 and pKa₂ = 11.29 Telluric add can be prepared by hydrolysis of tellurium hexafluoride according to the equation;

TeF₆ (g) + 6H₂O (l) → Te(OH)₆ (aq) + 6HF (aq)

Tellurium hexafluoride can be prepared by the reaction of elemental tellurium with fluorine gas:

Te (s) + 3F₂ (g) → TeF₆ (g)

If a cubic block of tellurium (density = 6.240 g/cm³) measuring 0.545 cm on edge is allowed to react with 2.34 L fluorine gas at 1.06atm and 25°C, what is the pH of a solution of Te(OH)₆ formed by dissolving the isolated TeF₆ (g) in 115 mL solution? Assume 100% yield in all reactions.