Neutralization calculator explained
Neutralization reactions consume acid and base equivalents in stoichiometric proportions. This calculator uses normality {normality}, sample volume {volume}, and solute mass {weight} to determine equivalent weight {equivalent_weight}, and it helps you apply the relationship to real titrations.
Use it when planning titrations, preparing buffers, or evaluating unknown acids by back-titration.
How the conversion works
For monoprotic acids and monobasic bases,
because one equivalent of acid neutralizes one equivalent of base. Normality () equals molarity times the number of acidic or basic protons. Equivalent weight is defined as the mass that supplies one equivalent:
The calculator takes mass per volume and divides by normality to return equivalent weight (in kilograms when inputs are SI; convert to grams if desired).
Units and conversions
| Quantity | Units | Notes |
|---|---|---|
| Normality | eq/L | e.g., 0.100 N HCl. |
| Volume | L | Convert mL by dividing by 1000. |
| Weight (mass) | g or kg | Mass of solute being characterized. |
| Equivalent weight | g/eq | Output describing how many grams provide one equivalent. |
Worked examples
- Acid volume needed for neutralization
Neutralize 35.0 mL of 0.150 N NaOH with HCl.
Convert volume to liters (0.0350 L), then solve for when :
- Equivalent weight of an unknown diprotic acid
A 0.250 g sample requires 25.0 mL of 0.100 N NaOH for the end point. Equivalents of base added:
The calculator mirrors this computation using {weight}, {volume}, and {normality}.
Tips and pitfalls
- Always convert volumes to liters when using normality in eq/L to keep units consistent.
- Multiply molarity by the number of acidic protons or hydroxide ions to obtain normality.
- Use primary standards (e.g., KHP) to standardize titrants before trusting neutralization results.
- When acids or bases are diprotic or triprotic, ensure the normality reflects the actual stoichiometry.