Solid calcium hydroxide is dissolved in water until the pH of the solution is 10.94. What is the hydroxide ion concentration [OH^-] of the solution? A) 3.06 M B) 1.1 ×10^-11 M C) 1.0 ×10^-14 M D) 8.7 ×10^-4 M E) none of these

Question

Quizplus · Accepted Answer

Calcium hydroxide (Ca(OH)2) dissociates in water to form calcium ions (Ca2+) and hydroxide ions (OH-). The dissociation equation is:

Ca(OH)2(s) → Ca2+(aq) + 2OH-(aq)

Since the pH of the solution is 10.94, we can use the equation:

pH = 14 - pOH

to calculate the pOH of the solution:

pOH = 14 - pH = 14 - 10.94 = 3.06

We know that:

pOH = -log[OH-]

So:

[OH-] = 10^-pOH = 10^-3.06 = 8.7 ×10^-4 M

Therefore, the hydroxide ion concentration of the solution is 8.7 ×10^-4 M, which is answer choice D.

Solid Calcium Hydroxide Is Dissolved in Water Until the PH