The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is __________.
i know the answer is 7.00, but im not sure how to solve it, do i create an ice chart?
Hi laney,
For this question, it would be appropriate for you to ask yourself.. what is present in the solution after mixing?
KOH is a strong basic salt while HCL is a strong acidic salt.
KOH + HCL --> KCL + H2O
Note that amount of KOH = HCL = 0.125 X (50/1000), so there is no limiting reagent which means that both KOH and HCL are completely used up. What's left in the solution in this case - is just KCL (and H2O).
This being an acid-base reaction of a strong acid and strong base, will form a neutral salt KCL. Since the salt and H2O are neutral, pH of the solution would be 7.00.
In this case, because both reactants are strong acids/bases, no calculation is needed since a neutral salt is produced.
Hope I helped! (:
-J
If necessary, you CAN calculate the pH at the neutral point.
HOH ==> H^+ + OH^-
Kw = (H^+)(OH^-) = 1 x 10^-14
(H^+) = (OH^-); therefore,
(H^+)^2 = 1 x 10^-14 and
(H^+) = 1 x 10^-7 M
pH = -log(H^+) = 7.0
To solve this problem, you do not need to create an ice chart. Instead, you can use the concept of neutralization reactions to determine the pH of the solution.
When an acid and a base react, they undergo a neutralization reaction to form water and a salt. In this case, KOH (potassium hydroxide) is a base and HCl (hydrochloric acid) is an acid. When they react, they will form water (H2O) and potassium chloride (KCl), a salt.
Since the concentration of KOH and HCl is the same (0.125 M) and the volumes are equal (50.0 mL each), the moles of KOH and HCl are equal as well.
The neutralization reaction is:
KOH + HCl -> KCl + H2O
From this balanced equation, you can see that the mole ratio between KOH and HCl is 1:1.
So, the moles of KOH reacted will be equal to the moles of HCl reacted. Since the concentrations and volumes of KOH and HCl are the same, the moles of KOH and HCl are also the same.
Therefore, all the KOH will react with all the HCl, resulting in complete neutralization. This means that all the hydronium ions (H+) and hydroxide ions (OH-) from the acid and base will combine to form water.
Water is a neutral substance with a pH of 7. Hence, the pH of the solution after neutralization will be 7.00.
To determine the pH of the solution formed by mixing KOH and HCl, you need to understand the concept of neutralization. When an acid and a base react, they undergo a neutralization reaction, resulting in the formation of salt and water. In this case, the reaction between KOH and HCl will result in the formation of water and KCl (potassium chloride):
KOH + HCl → KCl + H2O
Since both KOH and HCl are strong electrolytes, they completely dissociate in water, meaning that all the KOH and HCl will be converted into their respective ions. Therefore, the concentration of OH- ions from KOH will be equal to the concentration of H+ ions from HCl after complete ionization.
Given that the initial concentrations of KOH and HCl are both 0.125 M, the final concentrations of the OH- and H+ ions in the solution will also be 0.125 M.
Now, the pH of a solution can be calculated using the formula:
pH = -log [H+]
Since the concentration of H+ ions is 0.125 M, you can substitute this value into the equation:
pH = -log (0.125)
Using a calculator, the pH comes out to be 0.903.
However, since this is a neutralization reaction where equal volumes of KOH and HCl are mixed, the concentration of H+ ions and OH- ions will exactly neutralize each other. Therefore, the solution will be neutral, resulting in a pH of 7.00.
So, in this specific case, you don't need to create an ICE chart as it is a simple neutralization reaction resulting in a pH of 7.00.