Enter the sodium hydroxide concentration and select the input format into the calculator to determine the molarity in mol/L. The converter accepts g/L, % w/v, or mg/mL values.
Quick overview: NaOH to molarity
For sodium hydroxide, molarity is found by dividing the concentration in grams per liter by the molar mass of NaOH, which is approximately 40.00 g/mol.
- 10 g/L NaOH = 0.25 mol/L
- 20 g/L NaOH = 0.50 mol/L
- 40 g/L NaOH = 1.00 mol/L
- 100 g/L NaOH = 2.50 mol/L
If the concentration is given as % w/v, multiply by 10 to convert to g/L. If it is given as mg/mL, the numerical value is equal to g/L before dividing by 40.00.
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NaOH to Molarity Formula
The following formula is used to calculate the molarity of a sodium hydroxide solution when the concentration is expressed in grams per liter.
M = C / 40.00
Variables:
- M is the molarity of the NaOH solution in mol/L
- C is the sodium hydroxide concentration in g/L
- 40.00 is the approximate molar mass of NaOH in g/mol
To calculate the molarity, convert the sodium hydroxide concentration to grams per liter if necessary, then divide by 40.00. For % w/v, multiply the value by 10 to get g/L. For mg/mL, the numerical value is equal to g/L.
What is NaOH to Molarity Conversion?
NaOH to molarity conversion is the process of converting the concentration of a sodium hydroxide solution into moles per liter. Molarity is a standard chemistry concentration unit that tells you how many moles of dissolved substance are present in one liter of solution. Since sodium hydroxide has a molar mass of about 40.00 g/mol, the conversion is straightforward once the concentration is expressed in grams per liter.
This type of conversion is useful in laboratory preparation, titration work, chemical dosing, and solution comparison. By converting all concentration formats into molarity, different NaOH solutions can be compared on the same basis.
How to Calculate NaOH Molarity?
The following steps outline how to calculate the molarity of a sodium hydroxide solution.
- First, determine the NaOH concentration value.
- Next, identify the input format as g/L, % w/v, or mg/mL.
- If needed, convert the concentration to grams per liter.
- Finally, divide the concentration in g/L by 40.00 to calculate the molarity in mol/L.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
NaOH Concentration = 40 g/L
Molar Mass of NaOH = 40.00 g/mol
Molarity = 40 ÷ 40.00 = 1.00 mol/L
NaOH to Molarity Conversion Table
The table below summarizes several common sodium hydroxide concentrations and their corresponding molarity values using the formula M = (g/L) ÷ 40.00.
| NaOH Concentration (g/L) | Molar Mass Used (g/mol) | Molarity (mol/L) |
|---|---|---|
| 10 g/L | 40.00 | 0.25 mol/L |
| 20 g/L | 40.00 | 0.50 mol/L |
| 40 g/L | 40.00 | 1.00 mol/L |
| 80 g/L | 40.00 | 2.00 mol/L |
| 100 g/L | 40.00 | 2.50 mol/L |
| 200 g/L | 40.00 | 5.00 mol/L |
Laboratories and reference materials may report sodium hydroxide concentration in different units, but each can be converted to molarity by first expressing the solution strength in grams per liter and then dividing by 40.00 g/mol. This makes it easier to prepare solutions accurately and compare concentrations consistently.