Weak Acid Calculator
⚖ Acids, Bases & Equilibrium. Use the Weak acid formula to find [h⁺], ka, acid concentration: pick the value you want, type the others, and the answer updates as you go.
[H⁺]0.0013191 mol/L
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| [H⁺] | mol/L |
| Ka | no unit |
| Acid concentration | mol/L |
Worked example
Find the [h⁺] when Ka = 1.74 × 10⁻⁵, Acid concentration = 0.1 mol/L.
Using [H^+] = √(Ka Ca): [H⁺] = 0.0013191 mol/L.
Frequently asked questions
What is the formula for Weak acid?
[H^+] = √(Ka Ca).
What do the letters stand for, and what units are used?
[H⁺] in mol/L, Ka, Acid concentration in mol/L.
How do you calculate [h⁺]?
Put the values into [H^+] = √(Ka Ca). For example, with Ka = 1.74 × 10⁻⁵, Acid concentration = 0.1 mol/L, [h⁺] = 0.0013191 mol/L.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value ([h⁺], ka, acid concentration) and fill in the others: it rearranges the formula for you.
