Neutralization Calculator
Calculate the unknown variable in an acid-base neutralization reaction using the equation N1V1 = N2V2. Solve for normality or volume of acid or base.
⚗️ Acid-Base Neutralization
Acid
Base
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What Is Neutralization?
Neutralization is a chemical reaction in which an acid and a base react to form water and a salt. It is one of the most fundamental reactions in chemistry, occurring everywhere from industrial processes to the human stomach.
For a strong acid and strong base:
The Neutralization Equation
At the equivalence point of a neutralization (complete reaction), the number of acid equivalents equals the number of base equivalents:
Where:
- Na — Normality of the acid (equivalents per liter)
- Va — Volume of the acid
- Nb — Normality of the base
- Vb — Volume of the base
This can also be written using molarity and the n-factor:
Where na is the number of H+ ions per acid molecule and nb is the number of OH− ions per base molecule.
How to Use the Neutralization Formula
- Identify the acid and base in the reaction.
- Determine the normality of each solution. If given molarity, multiply by the n-factor (number of H+ or OH−).
- Measure the volumes used in the titration.
- Apply NaVa = NbVb and solve for the unknown.
50 mL of NaOH (0.1 N) is needed to neutralize 25 mL of HCl. Find the normality of HCl.
Na = Nb × Vb / Va = 0.1 × 50 / 25 = 0.2 N
Normality vs. Molarity in Neutralization
| Acid/Base | n-factor | Normality |
|---|---|---|
| HCl (monoprotic) | 1 | N = M × 1 |
| H2SO4 (diprotic) | 2 | N = M × 2 |
| H3PO4 (triprotic) | 3 | N = M × 3 |
| NaOH (monobasic) | 1 | N = M × 1 |
| Ca(OH)2 (dibasic) | 2 | N = M × 2 |
| Al(OH)3 (tribasic) | 3 | N = M × 3 |
Titration and Neutralization
Titration is the laboratory technique used to determine the unknown concentration of a solution by reacting it with a solution of known concentration (the titrant). In an acid-base titration:
- A measured volume of the unknown solution is placed in a flask.
- The titrant is slowly added from a burette.
- An indicator (e.g., phenolphthalein, methyl orange) signals the equivalence point by changing color.
- The volume of titrant used is recorded, and the unknown concentration is calculated using NaVa = NbVb.
Common Indicators for Acid-Base Titrations
| Indicator | pH Range | Acid Color | Base Color |
|---|---|---|---|
| Methyl orange | 3.1–4.4 | Red | Yellow |
| Bromothymol blue | 6.0–7.6 | Yellow | Blue |
| Phenolphthalein | 8.2–10.0 | Colorless | Pink |
| Litmus | 5.0–8.0 | Red | Blue |
Heat of Neutralization
Neutralization is an exothermic reaction. For strong acid + strong base in dilute aqueous solution, the heat released is approximately:
This value is nearly constant because the net ionic reaction is always: H+ + OH− → H2O.
Frequently Asked Questions
What is the equivalence point?
The equivalence point is the moment when the number of moles of acid equals the number of moles of base (in terms of equivalents). At this point, neutralization is complete. For a strong acid + strong base titration, the pH at the equivalence point is 7.0.
Can I use molarity instead of normality?
Yes, but you must account for the n-factor: Ma × na × Va = Mb × nb × Vb. For monoprotic acid and monobasic base, normality equals molarity, so MaVa = MbVb.
What happens after the equivalence point?
Adding more acid or base beyond the equivalence point creates an excess of H+ or OH−, shifting the pH significantly. The solution is no longer neutral.