- A 10M sodium hydroxide (NaOH) stock solution is used for many applications including adjusting the pH of various solutions.
- The Normality of NaOH solution is equal to the molarity of the solution. This means that the normality of a 10M solution of NaOH is equal to 10N.
- The molecular weight of NaOH is 40. This means you need to dissolve 40 g of NaOH in water to obtain a 1 liter of 1M (or 1N) NaOH solution. To prepare a 10M NaOH solution, you need to dissolve 10 times more NaOH i.e., 400 g of NaOH for 1 L solution.
- Here we will prepare 100 ml of 10M NaOH solution. Therefore, we need to take 40 g of NaOH.
- Dissolution of NaOH is a hyperthermic reaction (generates heat), therefore, NaOH is added in water in small quantities instead of adding all at a time to limit the heat generation as excessive heat can damage the container (glass beaker).
Reagents and solutions
Sodium hydroxide (NaOH) pallet
Deionized / Double distilled water
Equipment and disposables
Measuring cylinder/volumetric flask
Erlenmeyer flask / Beaker
Glass rod/Magnetic stirrer
Ice bucket with ice (optional)
10 M NaOH solution
Preparation of 100 ml of 10 M NaOH solution in water
Use personal protective equipment (lab coat, gloves, goggles etc) for your safety and follow the guidelines of your institute.
Step 1: To prepare 100 ml of 10 M NaOH solution, weigh out 40 g of NaOH (molecular weight: 40).
Don’t expose solid NaOH to air for a long time while weighing. NaOH is hygroscopic in nature and absorbs water from the atmosphere quickly.
Step 2: Dissolve NaOH pellets in 70 ml water by adding small quantities of NaOH in water.
◊ Take 70 ml of deionized/double distilled water in a beaker.
◊ Add a few pellets (4 – 5 pellets each time) of NaOH in water and wait until they dissolve. Repeat this until all 40 g NaOH pellets are dissolved in water.
1. The dissolution of NaOH is a highly exothermic reaction, which can even break the glass beakers. It is recommended to keep the beaker on ice while dissolving NaOH.
2. Never add 70 ml water to 40 g NaOH pellet.
Step 3: Adjust the solution volume to 100 ml with deionized/double distilled water.
◊ Transfer solution to a measuring cylinder/volumetric flask (capacity: 100 ml) and adjust the volume to 100 ml with deionized/double distilled water.
The solution can be stored at room temperature for several months.
There is no need to sterilize this solution by autoclaving. No microorganism will grow in concentrated NaOH solution.
● NaOH is a strong base and is commonly used to adjust the pH of many solutions.
● Plasmid isolation by alkaline lysis method
● Preparation of EDTA solution
|Follow the table to prepare NaOH solution of specific concentration and volume|
|Conc. / Volume||50 ml||100 ml||250 ml||500 ml|
|1 M||2.00 g||4.00 g||10.00 g||20.00 g|
|2 M||4.00 g||8.00 g||20.00 g||40.00 g|
|5 M||10.00 g||20.00 g||50.00 g||100.00 g|
|10 M||20.00 g||40.00 g||100.00 g||200.00 g|
Use calculator to calculate the quantities of NaOH for the preparation of NaOH solution of specific concentration and volume
Molecular weight of NaOH: 40
Volume of Sodium hydroxide solution: ml
(change the volume of the solution)
Molarity of Sodium hydroxide solution: M
(Change the molarity of the solution)
Amount of sodium hydroxide: 40 g