50.00mL of 0.250M hydrochloric acid was added to 25.00mL of 0.300M potassium hydroxide.
Calculate the pH of the resulting solution.
12.5 mM HCl and 7.5 mM KOH
after netralization ... 5.0 mM HCl in
75.0 mL of solution ... .067 M HCl
pH = -log[H⁺] = -log[.067]
To calculate the pH of the resulting solution, we need to determine the concentration of the resulting solution after the reaction between hydrochloric acid (HCl) and potassium hydroxide (KOH) occurs. This is a neutralization reaction where an acid reacts with a base to form a salt and water.
First, we can calculate the moles of hydrochloric acid (HCl) and potassium hydroxide (KOH) using the formula:
moles = concentration (M) x volume (L)
Moles of HCl = 0.250 M x 0.0500 L = 0.0125 moles
Moles of KOH = 0.300 M x 0.0250 L = 0.0075 moles
Since HCl and KOH react in a 1:1 ratio, the amount of HCl that reacts completely with KOH will be equal to the amount of KOH used. So, we have 0.0075 moles of HCl that react.
Now, we need to determine the moles of any excess or remaining HCl in the solution. This can be done by subtracting the moles of HCl that reacted from the initial moles of HCl:
Remaining moles of HCl = Initial moles of HCl - Moles of HCl that reacted
Remaining moles of HCl = 0.0125 moles - 0.0075 moles = 0.0050 moles
Next, we need to determine the total volume of the resulting solution. To do this, we add the volumes of the hydrochloric acid and potassium hydroxide together:
Total volume of resulting solution = Volume of HCl + Volume of KOH
Total volume of resulting solution = 0.0500 L + 0.0250 L = 0.0750 L
Now, we can calculate the concentration of the resulting solution:
Concentration of resulting solution = Moles of HCl / Total volume of resulting solution
Concentration of resulting solution = 0.0050 moles / 0.0750 L = 0.067 M
Finally, to calculate the pH of the resulting solution, we can use the following formula for a strong acid:
pH = -log10(Concentration of H+ ions)
Since hydrochloric acid is a strong acid and completely dissociates in water, the concentration of H+ ions in the resulting solution is equal to the concentration of the resulting solution.
pH = -log10(0.067) = 1.18
Therefore, the pH of the resulting solution is 1.18.