* Neutralization Reaction: HCl (a strong acid) and NaOH (a strong base) react in a 1:1 molar ratio to form water (H2O) and salt (NaCl):
HCl + NaOH → H2O + NaCl
* Molarity and Volume: The pH of the final solution depends on the amount of excess acid or base remaining after the reaction. This is determined by the initial volumes of the HCl and NaOH solutions.
Example Scenarios:
* Equal Volumes: If you mix equal volumes of 1N HCl and 1N NaOH, the solution will be perfectly neutralized, resulting in a pH of 7 (neutral).
* More HCl: If you have more HCl than NaOH, the resulting solution will be acidic, and the pH will be less than 7.
* More NaOH: If you have more NaOH than HCl, the resulting solution will be basic, and the pH will be greater than 7.
To Calculate the pH:
1. Determine the moles of HCl and NaOH:
* moles = Molarity (N) x Volume (L)
2. Identify the limiting reactant: The reactant with fewer moles is the limiting reactant.
3. Calculate the moles of excess reactant: Subtract the moles of the limiting reactant from the moles of the excess reactant.
4. Calculate the concentration of the excess reactant: Divide the moles of the excess reactant by the total volume of the mixture.
5. Determine the pH:
* If the excess reactant is HCl: pH = -log[H+]
* If the excess reactant is NaOH: pOH = -log[OH-], then pH = 14 - pOH
Remember: Always work with volumes in liters (L) for accurate calculations.
