a saturated solution of milk of magnesia, Mg(OH)2, has a pH of 10.5. What is the hydronium concentration of the solution? is the solution acidic or basic?

To find the hydronium concentration of the solution, we can use the relationship between pH and hydronium concentration. The pH scale is logarithmic, so we can convert pH to hydronium concentration using the formula:

[H3O+] = 10^(-pH)

Substituting the given pH value of 10.5 into the equation:

[H3O+] = 10^(-10.5)

Calculating this value:

[H3O+] = 3.16 x 10^(-11) mol/L

Now, to determine whether the solution is acidic or basic, we can compare the hydronium concentration ([H3O+]) to the neutral range of pH, which is 7. If [H3O+] is less than 10^(-7) mol/L, the solution is basic. If [H3O+] is greater than 10^(-7) mol/L, the solution is acidic.

In this case, the hydronium concentration is 3.16 x 10^(-11) mol/L, which is less than 10^(-7) mol/L. Therefore, the solution is basic.

To find the hydronium concentration of the solution, you will need to solve for the concentration of hydroxide ions (OH-) first, and then use the concept of the autoionization of water. The autoionization of water is a process in which water molecules act as both acids and bases, leading to the formation of hydronium ions (H3O+) and hydroxide ions in a reversible reaction:

H2O ⇌ H3O+ + OH-

The equilibrium constant for this reaction, called the water ion product or Kw, is equal to 1.0 x 10^-14 at 25°C.

Since the solution is saturated milk of magnesia (Mg(OH)2), it produces magnesium hydroxide (Mg(OH)2) and hydroxide ions (OH-). In a saturated solution, the concentration of the dissolved solute is in equilibrium with the solid form.

The balanced equation for the dissolution of magnesium hydroxide is:

Mg(OH)2 -> Mg2+ + 2OH-

From the equation, we can see that each molecule of Mg(OH)2 produces 2 OH- ions. Therefore, the concentration of OH- ions is twice the concentration of dissolved Mg(OH)2.

Given that the pH of the solution is 10.5, we can use the pH scale to determine the concentration of hydroxide ions. The pH scale is a logarithmic scale ranging from 0 to 14, with 7 being neutral, and values below 7 indicating acidity, while values above 7 indicating basicity.

To calculate the concentration of hydroxide ions (OH-) corresponding to the given pH of 10.5, you need to convert the pH to the H+ ion concentration, then use the autoionization of water equation to convert that to the OH- ion concentration.

Using the relationship pH = -log[H+], we can solve for [H+], which represents the concentration of hydronium ions:

pH = 10.5
[H+] = 10^(-pH)
[H+] = 10^(-10.5)

Now, using the equation Kw = [H+][OH-], with Kw = 1.0 x 10^-14, we can substitute the [H+] value and solve for [OH-]:

1.0 x 10^-14 = (10^(-10.5))[OH-]
[OH-] = (1.0 x 10^-14) / (10^(-10.5))

Simplifying the equation above, we can calculate the value of [OH-]:

[OH-] = 1.0 x 10^(-14 + 10.5)
[OH-] = 1.0 x 10^(-3.5)
[OH-] = 3.16 x 10^(-4) M

So, the concentration of hydroxide ions (OH-) in the saturated solution of milk of magnesia is approximately 3.16 x 10^(-4) M.

Since the concentration of hydroxide ions (OH-) is greater than the concentration of hydronium ions (H3O+), the solution is considered basic or alkaline.

The definition of pH is:

pH=-log[H3O+]
An equivalent statement is:
[H3O+] = 10^-pH
The hydronium concentration is the antilog of the (-pH)
For this example,
[H3O+] = 10^-10.5 = ??
The definition acid, basic, and neutral pH's should be something you can look up in your textbook or other assigned materials.