16 Calculate The Ph of 0.0075 M Sr Oh 2

How to Calculate the pH of Sr(OH)2

The pH of a solution containing Sr(OH)2 can be calculated using the following steps:

1. Determine the concentration of the hydroxide ions (OH⁻) in the solution.
2. Calculate the pOH using the hydroxide ion concentration.
3. Convert pOH to pH using the relationship between pH and pOH.

For a strong base like Sr(OH)2, the concentration of hydroxide ions is equal to the concentration of the base itself, assuming complete dissociation.

The pH Calculation Formula

The pH of a solution can be calculated using the following formula:

For Sr(OH)2, since it's a strong base, [OH⁻] = [Sr(OH)2] = 0.0075 M.

Worked Example

Let's calculate the pH of a 0.0075 M Sr(OH)2 solution:

1. First, calculate the pOH:

   pOH = -log[0.0075]

   pOH ≈ -log(7.5 × 10⁻³)

   pOH ≈ 2.122

2. Then, calculate the pH:

   pH = 14 - pOH

   pH = 14 - 2.122

   pH ≈ 11.878

Therefore, the pH of a 0.0075 M Sr(OH)2 solution is approximately 11.88.

Interpreting the Results

A pH of approximately 11.88 indicates that the solution is strongly alkaline. This is expected since Sr(OH)2 is a strong base that completely dissociates in water.

Key points to remember:

• pH values below 7 are acidic
• pH values above 7 are alkaline
• Each whole number change in pH represents a tenfold change in acidity or alkalinity