Preparation and Standardization of 0.1 M Sodium Hydroxide

How to prepare 0.1 m sodium hydroxide ?

Preparation of 0.1 M Sodium Hydroxide (NaOH) or 0.1 N Sodium Hydroxide (NaOH):

  • Take a 100 mL of purified water or water in 1000 mL volumetric flask. Add 4.0 g of Sodium Hydroxide (NaOH) carefully using calibrated Balance.
  • Add approx. 700 mL water. Allow Solution to *cool down to Room Temperature.
  • Make up the volume upto 1000 mL with purified water.

 * Because of Thermodynamic reaction volume may vary, so final volume shall be added after partial addition of volume.


  • Molecular weight of Sodium Hydroxide (NaOH)= 40g
  • Equivalent Weight of Sodium Hydroxide (NaOH)= 40/1= 40g
  • 40 gm of Sodium Hydroxide (NaOH) in 1000mL Water= 1N NaOH
  • 20gm of Sodium Hydroxide (NaOH) in 1000mL Water= 0.5 N NaOH
  • 4.0 gm of Sodium Hydroxide (NaOH) in 1000mL Water= 0.1 N NaOH

Standardizing a 0.1 N Sodium Hydroxide (NaOH) Solution

1. Standardizing a Sodium Hydroxide (NaOH) Solution using potassium hydrogen phthalate (KHP)

  • To standardize the 0.1 M NaOH solution (the titrant) with potassium hydrogen phthalate (KHP, Formula: KC8H4O4H) using phenolphthalein as the indicator.
  • Dry primary standard potassium hydrogen phthalate (KHP) for about two hours at 120°C in Oven.
  • Accurately Weigh 500 mg of previously dried potassium hydrogen phthalate (KHP) (Molecular Weight = 204.23 g/mol) into a flask.
  • Dissolve your sample in 75 mL of carbon dioxide free water.
  • Add 2-4 drops of phenolphthalein as an indicator into the flask (Erlenmeyer Flask).
  • Obtain approximately 100 mL of NaOH solution in a clean, dry beaker.
  • Prepare the burette for titration by rinsing with 2 aliquots of solution. Fill the burette and record the initial volume to 0.1 mL.
  • Begin titrating when pink appears for the first time. To determine the total amount most accurately, add the NaOH dropwise toward the endpoint.
  • Record the final burette reading. If time allows, repeat the titration.


Normality of NaOH = (weight of KHP ) ÷ 0.20422 * mL used of NaoH solution in titration.

Potassium hydrogen phthalate (KHP) Synonym(s): Phthalic acid monopotassium salt, Potassium phthalate monobasic, KHP, Potassium biphthalate.

Related : Preparation and Standardization of 1 N Sulfuric Acid

2. Standardizing a Sodium Hydroxide (NaOH) Solution using Oxalic Acid (H2C2O4. 2H2O)

  • Titration of Sodium Hydroxide (NaOH) and Oxalic Acid Solution, Clean the burette carefully, than wash it with distilled water and finally rinse it with sodium hydroxide (NaOH) solution.
  • Rinse the burette well with the solution that will be used in it. In a burette stand, clamp the burette vertically.
  • Fill 0.1 N Sodium hydroxide (NaoH) solution into the burette using funnel above the zero mark.
  • By vigorously flowing the solution from the burette nozzle, remove any air traps that may      have formed.
  • Pipette out 10 mL of oxalic acid solution in a washed and dried conical flask.
  • Add 1-2 drops of phenolphthalein indicator to the conical flask.
  • Place the flask over the glazed tile. Titrate the acid with sodium hydroxide solution till a very faint permanent pink colour is obtained. (Take 20 mL of 0.5 N Oxalic Acid to start the titration)
  • Add sodium hydroxide solution in small drop wise.
  • In the burette, read the lower meniscus of the solution once again and record it as the final reading.
  • Repeat the procedure for 3 (three) concordant readings are obtained.


  • Molecular weight of Oxalic Acid = 126 g,
  • Equivalent weight of Oxalic Acid =63 g (as, 126/2)
  • 63 g of Oxalic Acid in 1000 mL of Purified Water= 1 N Oxalic Acid
  • 31.5 g of Oxalic Acid in 1000 mL of Purified Water= 0.5 N Oxalic Acid

  • Molarity of NaOH solution can be calculated by using the equation:

Oxalic acid                Sodium hydroxide

a1 M1V1           =       a2 M2V2


  • M1 and V1 = molarity and volume of the oxalic acid solution.
  • M2 and V2 = molarity and volume of the sodium hydroxide solution.
  • a1 and a2 = the basicity of oxalic acid and acidity of sodium hydroxide.


  • a1= 2 and a2 = 1.


Molar mass:  

  • Oxalic acid, [(COOH) 2.2H2O] = 126 g mol–1
  • Sodium hydroxide (NaOH) = 40 g mol –1
  • Calculate the con. of sodium hydroxide (NaOH) solution in g/L by using the equation given below.

Concentration (strength) in g/L = Molarity (M) × Molar mass

3. Standardization of a 0.1 N sodium hydroxide (NaOH) solution using Benzoic Acid

  • Equation:

HC7H5O2(aq) + NaOH(aq) = NaC7H5O2(aq) + H2O(l)

  • Dissolve around 200 mg of benzoic acid in 100 mL of carbon dioxide-free water, warm until completely dissolved, and cool down to RT (Room Temperature).
  • Add 2 drops of phenolphthalein as an indicator.
  • Titrate with 0.1 N sodium hydroxide with benzoic acid until a permanent pale pink color is produced.


  • The molar mass of benzoic acid =122.12 g/mol.

Normality of NaOH = (weight of Benzoic Acid) ÷ (122.1 * mL of NaOH used)

Preparation and Standardization of 0.1 M Sodium Hydroxide

Related: Preparation and Standardization of 0.1N Hydrochloric Acid (HCl)

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