Answer:
pH = 12.7
Explanation:
First, we have to calculate the [Ca²⁺] in a solution of about 250 ppm CaCO₃.
Now, let's consider the dissolution of Ca(OH)₂ in water.
Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)
The solubility product Ksp is:
Ksp = [Ca²⁺] × [OH⁻]²
[OH⁻] = √(Ksp/[Ca²⁺]) = √(6.5 × 10⁻⁶/2.5 × 10⁻³) = 5.1 × 10⁻² M
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log (5.1 × 10⁻²) = 1.3
pH + pOH = 14 ⇒ pH = 14 - pOH = 14 - 1.3 = 12.7
I think the answer is letter B.
Answer:
2.067 x 10⁻⁷ M/min.
Explanation:
- Knowing that the rate of the reaction is the change in the concentration of reactants (decrease) or the products (increase) with time.
- For the reaction: <em>2NOCl ⇄ 2NO + Cl₂,</em>
<em>Rate of the reaction = - 1/2 d[NOCl]/dt = 1/2 d[NO]/dt = d[Cl₂]/dt</em>
∵ d[Cl₂] = 3.39 x 10⁻³ M, dt = 1.64 x 10³ min.
∴ Rate of the reaction = d[Cl₂]/dt = (3.39 x 10⁻³ M) / (1.64 x 10³ min) = 2.067 x 10⁻⁷ M/min.
3.) Charge on one molecule of PO4 is -3. So on two molecule it'll be 2(-3) = -6. Let oxidation number of Pb be x. Therefore, 3x+(-6) = 0. 3x=6. x=2.
