Preparation and Titration of 0.2N HCl

To prepare a 0.2N HCl solution, you need to dilute concentrated hydrochloric acid with distilled water. Step-by-step process.

Apparatus Requirement

• Concentrated HCl 37%
• Distilled Water
• Volumetric Flask 1lit.
• pipette or burette
• Safety goggles and gloves

Prepare the Solution

• Measure 16.67 ml of concentrated HCl
• Add this HCl slowly to a volumetric flask containing about 700-800 ml of distilled water (add acid to water to avoid heat-related hazards)
• Fill the flask with distilled water up to the 1000 ml mark and shak.

Titration of 0.2N HCl

Titration is used to determine the concentration or verify the normality of the prepared 0.2N HCl solution by reacting it with a standard solution (e.g., 0.1N NaOH).

Apparatus Requirement

• Prepared 0.2N HCl solution
• 0.1N NaOH (standard solution)
• Burette
• Pipette
• Conical flask
• Phenolphthalein or Methyl Red indicator
• Distilled water

Process

10ml HCl (0.2N)

3-5 drop Phenolphthalein Indicator

Titrate with 0.1N NaOH

End colour pink appears

Calculation

( 1 )Normality of NaOH × T.V. ÷ Volume of HCl = Normality of HCl

Example: 0.1N × 20.1 ml ÷ 10 ml = 0.201N (close to 0.2N, with slight variation due to experimental error).

( 2 ) Alternatively: V1N1 = V2N2

• V1 = 10 ml (HCl)
• N1 = ? (to find)
• V2 = 20.1 ml (NaOH)
• N2 = 0.1N

N1 = (V2 × N2) ÷ V1

= (20.1 × 0.1) ÷ 10

= 0.201N

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