Preparation of 10 M Sodium Hydroxide (NaOH) Solution

OVERVIEW

  • 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. That 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).

Requirements

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)
Weighing Balance

Composition
10 M NaOH solution

Objective
Preparation of 100 ml of 10 M NaOH solution in water

Preparation

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).

Precaution:
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 the water.
◊ Take 70 ml 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.

Precautions: 
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 of 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.

Storage:
The solution can be stored at room temperature for several months.

Note: 
There is no need to sterilize this solution by autoclaving. No microorganism will grow in concentrated NaOH solution. 

Applications
●  NaOH is a strong base and 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. / Volume50 ml100 ml250 ml500 ml
1 M2.00 g4.00 g10.00 g20.00 g
2 M4.00 g8.00 g20.00 g40.00 g
5 M10.00 g20.00 g50.00 g100.00 g
10 M20.00 g40.00 g100.00 g200.00 g

CALCULATOR

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: g



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