195k views
3 votes
Ksp for Cu(OH)2 is 4.8 x 10⁻²⁰. What is the pH of the saturated solution of Cu(OH)₂?

a) 2.3
b) 4.8
c) 10.7
d) 12.3

User Bobdiaes
by
7.8k points

1 Answer

6 votes

Final answer:

The pH of a saturated solution of Cu(OH)₂, we can use the Ksp expression and the relationship between pH and pOH. The pH of the solution is approximately 7.14.

Step-by-step explanation:

To determine the pH of a saturated solution of Cu(OH)₂, we need to consider the equilibrium reaction that occurs when Cu(OH)₂ dissolves in water:


Cu(OH)₂ ⇌ Cu²+ + 2OH¯


The Ksp expression for this reaction is Ksp = [Cu²+][OH¯]². Given that the Ksp value for Cu(OH)₂ is 4.8 x 10⁻²⁰, we can set up the equation as follows:


4.8 x 10⁻²⁰ = x(2x)²


Simplifying the equation and solving for x, we find that x is approximately 1.38 x 10⁻⁷. This represents the concentration of OH¯ ions in the saturated solution.


To find the pH, we can use the equation: pOH = -log[OH¯]. Substituting the concentration of OH¯ into the equation, we get:


pOH = -log(1.38 x 10⁻⁷) ≈ 6.86


Finally, we can use the relationship between pH and pOH (pH + pOH = 14) to find the pH:


pH = 14 - 6.86 ≈ 7.14


Therefore, the pH of the saturated solution of Cu(OH)₂ is approximately 7.14. The correct answer is not provided in the options given.

User Sean Pearce
by
7.3k points