Understanding Normality and pH
* Normality (N): Represents the number of equivalents of a solute per liter of solution. For NaOH, one mole contains one equivalent of hydroxide ions (OH-). So, a 1N solution of NaOH is the same as a 1M (1 Molar) solution.
* pH: A measure of the acidity or alkalinity of a solution. It's based on the concentration of hydrogen ions (H+) in the solution.
Calculating pH
1. Dissociation: NaOH dissociates completely in water, forming one sodium ion (Na+) and one hydroxide ion (OH-):
NaOH → Na+ + OH-
2. Hydroxide Ion Concentration: Since a 1N solution of NaOH contains 1 mole of NaOH per liter, the concentration of OH- ions is also 1 M.
3. pOH: The pOH is a measure of the hydroxide ion concentration:
pOH = -log[OH-] = -log(1) = 0
4. pH Calculation: The pH and pOH are related by the following equation:
pH + pOH = 14
Therefore, pH = 14 - pOH = 14 - 0 = 14
Conclusion
The pH of a 1N solution of sodium hydroxide is 14. This indicates a highly alkaline solution.
