Question

Solve for the pH of (Mg(OH)₂) in (0.0025 M).

a) 10.3

b) 9.7

c) 8.3

d) 7.0

Answer 1

The pH of a 0.0025 M Mg(OH)₂ solution is 11.70. This does not match the given options.

Step-by-step explanation:

The question asks to solve for the pH of a 0.0025 M Mg(OH)₂ solution. Mg(OH)₂ is a strong base that dissociates completely in water to Mg₂⁺ and OH⁻ ions. Since each molecule of Mg(OH)₂ produces two OH⁻ ions, the concentration of OH⁻ will be twice the concentration of Mg(OH)₂, which is 0.0050 M.

Now, we can calculate the pOH using the formula pOH = -log [OH⁻], and then find the pH by the relation: pH = 14 - pOH. The pOH can be calculated as follows:

pOH = -log [0.0050] = 2.30 (2 decimal places since 0.0050 has 2 significant figures)

Therefore, pH = 14 - 2.30 = 11.70. Among the given options, none matches the correct pH value.