Calculate the solubility of CaF2 in g/L (Ksp = 4.0 x 10-8). 2. What is the pH of a solution containing a hydrogen ion concentration of 3.0x10-4M? 3. What is the oxidizing agent and reducing agent in the following reaction: Zn(s) + Cl2(g) → ZnCl2(s) 4. Assign the oxidation numbers of the atoms in the following compounds. (a) Al2O3 (b) XeF4 (c) K2Cr2O7

Explanation:

1. Solubility of CaF_2

(a) Molar solubility

CaF₂ ⇌ Ca²⁺ + 2F⁻

(b) Mass solubility

2. pH

pH = -log [H⁺] = -log(3.0 × 10⁻⁴) = 3.52

3. Oxidizing and reducing agents

Zn + Cl₂ ⟶ ZnCl₂

The oxidation number of Cl has decreased from 0 to -1.

Cl has been reduced, so Cl is the oxidizing agent.

4. Oxidation numbers

(a) Al₂O₃

1O = -2; 3O = -6; 2Al  = +6; 1Al = +3

(b) XeF₄

1F = -1; 4F = -4; 1 Xe = +4

(c) K₂Cr₂O₇

1K = +1; 2K = +2; 1O = -2; 7O = -14

+2 - 14 = -12

2Cr = + 12; 1 Cr = +6

2b2t

explanation:

2b2t