Calculator Inputs
Formula Used
At the equivalence point, acid equivalents equal base equivalents. The core relation is:
Ma × Va × acid factor = Mb × Vb × base factor
Therefore:
Ma = (Mb × Vb × base factor) ÷ (Va × acid factor)
When the unknown acid sample was diluted before titration, the final stock molarity is:
Stock Ma = calculated aliquot Ma × dilution factor
The blank corrected titre is:
Corrected Vb = measured titre − blank volume
Example Data Table
| Base molarity | Acid volume | Titre volume | Acid factor | Base factor | Dilution factor | Unknown acid molarity |
|---|---|---|---|---|---|---|
| 0.100 M | 25.00 mL | 24.80 mL | 1 | 1 | 1 | 0.0992 M |
| 0.250 M | 20.00 mL | 18.50 mL | 2 | 1 | 5 | 0.578125 M |
| 0.050 M | 10.00 mL | 12.60 mL | 1 | 2 | 10 | 1.26 M |
How to Use This Calculator
- Enter the molarity of the known base used in titration.
- Add the measured acid aliquot volume.
- Enter burette readings or paste several trial titre volumes.
- Use blank correction when a reagent blank was measured.
- Set acid and base factors from the balanced neutralization equation.
- Add a dilution factor when the original acid sample was diluted.
- Enter molar mass if you need g/L or percent strength.
- Press calculate and download the result as needed.
Understanding Unknown Acid Molarity
Why Titration Works
Acid molarity is often found by titration. A known base is added to a measured acid sample. The endpoint shows when the reaction is complete. At that point, the reacting acid and base match through their chemical equation. This calculator uses that balance to find the unknown acid concentration.
Role of Stoichiometry
Simple titrations often use a one to one ratio. Hydrochloric acid and sodium hydroxide are common examples. Other reactions are different. Sulfuric acid can donate two hydrogen ions. Calcium hydroxide can provide two hydroxide ions. These factors change the final answer. The acid factor and base factor handle these cases.
Why Blank Correction Matters
A blank correction removes volume caused by reagents, indicators, or background reaction. This is useful in careful laboratory work. Without the correction, the titre can appear too large. That can make the acid molarity too high. Small corrections matter most when sample volumes are small.
Using Several Trials
Repeated titrations improve confidence. Concordant titres show good technique and stable measurements. The calculator accepts multiple trial volumes. It averages the corrected titres. It also reports standard deviation and relative standard deviation when several trials are entered.
Diluted Acid Samples
Many acid samples are too concentrated for direct titration. A small portion may be diluted to a known volume. The titration then measures the diluted aliquot. The original stock molarity is found by multiplying by the dilution factor. This keeps the final result linked to the original unknown acid.
Reporting the Result
The main result is molarity in moles per liter. Optional molar mass converts the answer into grams per liter and percent weight by volume. The approximate pH is only a rough strong acid estimate. Real weak acids need equilibrium data. For lab reports, include units, factors, titre readings, and the balanced reaction.
FAQs
What is unknown acid molarity?
It is the concentration of an acid sample when its exact strength is not known. It is usually reported in moles per liter.
Which base value should I enter?
Enter the standardized molarity of the base used in the titration. Do not use an estimated label value if a standardized value is available.
What is the acid factor?
The acid factor is the number of acidic hydrogen ions reacting per acid molecule. For hydrochloric acid it is 1. For sulfuric acid it is commonly 2.
What is the base factor?
The base factor is the number of hydroxide ions supplied per base formula unit. Sodium hydroxide has 1. Calcium hydroxide has 2.
Can I use several titre readings?
Yes. Enter the titre volumes separated by commas, spaces, or new lines. The calculator averages them and reports variation when possible.
When should I use blank correction?
Use blank correction when a blank titration was performed. It removes volume caused by reagents or background effects rather than the unknown acid.
What does dilution factor mean?
It tells how much the original acid was diluted before titration. Use 1 if no dilution was made. Use 10 for a tenfold dilution.
Is the pH result exact?
No. The pH shown is only a simple strong acid estimate. Weak acids require acid dissociation constants and equilibrium calculations.