Final answer:
To calculate the pH of a strong mono hydroxyl ionic basic solution, you must first determine the hydroxide ion concentration, then calculate the pOH, and finally subtract the pOH from 14 to get the pH. An example calculation for a solution of NaOH results in a basic pH value.
Step-by-step explanation:
To find the pH of a strong mono hydroxyl ionic basic solution, follow these steps:
- Determine the concentration of the hydroxide ions (OH-) in the solution. For a strong base like sodium hydroxide (NaOH), it will dissociate completely in water, so the molarity of the base will be the same as the concentration of hydroxide ions.
- Calculate the pOH of the solution by taking the negative logarithm (base 10) of the hydroxide ion concentration. In formula terms, pOH = -log[OH-].
- Find the pH by subtracting the pOH from 14. So, pH = 14 - pOH.
- For example, if you have a 1.0 L solution with 1.0 g of NaOH dissolved in it, first convert the mass of NaOH to moles (NaOH has a molar mass of about 40 g/mol), which gives us 0.025 moles. This is the concentration of hydroxide ions since it's a strong base hence [OH-] = 0.025 M.
- Next, compute the pOH = -log(0.025) which is approximately 1.60.
- Finally, subtract the pOH from 14 to get the pH. So, pH = 14 - 1.60 = 12.40.
This process results in a basic pH since the pH is above 7.