Assay of Ammonium Chloride

Assay of Ammonium Chloride by Acid-Base Titration

Aim: To perform the assay of ammonium chloride by acid-base titration. 

Requirements: 

  • Apparatus: Beaker, Funnel, Pipette, Burrette. 
  • Chemicals: Ammonium chloride, Potassium hydrogen phthalate, Phenolphthalein, Sodium hydroxide solution. 

Monograph: Ammonium chloride. 

NH4Cl Molecular weight 53.5. 

Ammonium chloride contains not less than 99.0 per cent and not more than 100.5 per cent of Cl, calculated on a dried basis. 

  • Category: Expectorant; diuretic; systemic acidifier. 
  • Dose: 3 to 6 g daily, in divided doses. 
  • Description: Colourless crystals or a white crystalline powder. 

Procedure: 

(A) Standardisation of NaOH:  Weigh accurately about 5 g of potassium hydrogen phthalate previously powdered and dried at 120°C for 2 hours, and dissolve in 75 ml carbon dioxide-free water. Add 0.1 ml phenolphthalein solution and titrate with the sodium hydroxide solution until a permanent pink colour is produced. 1 ml of 1 M sodium hydroxide is equivalent to 0.2042 g of potassium hydrogen phthalate. 

(B) Assay:  Weigh accurately about 0.1 g, dissolve in 20 ml of water and add a mixture of 5 ml of formaldehyde solution, previously neutralised to dilute phenolphthalein solution, and 20 ml of water. After 2 minutes, titrate slowly with 0.1 M sodium hydroxide using a further 0.2 ml of dilute phenolphthalein solution as an indicator. 

1 ml of 0.1 M sodium hydroxide is equivalent to 0.005349 g of NH4Cl. 

Observation Table: (Standardization)

Sr. No.ParametersReading
1.Burette solutionNaOH solution 
2.Conical flask solutionPotassium hydrogen phthalate, water 
3.IndicatorPhenolphthalein 
4.EndpointColourless to pink
Burette reading (B.R) (ml)Trial 1Trial 2Trial 3Average (BR)
     

Observation table: (Assay) 

Sr. No.ParametersReading
1.Burette solutionNaOH solution 
2.Conical flask solutionAmmonium chloride, Formaldehyde
3.IndicatorPhenolphthalein 
4.EndpointColourless to pink
Burette reading (B.R) (ml)Trial 1Trial 2Trial 3Average (BR)
     

Factor: 1 ml of 0.1 M sodium hydroxide is equivalent to 0.005349 g of NH4Cl. 

Result: The % purity of ammonium chloride is …….

Make sure you also check our other amazing Article on : Standardization of Potassium Permanganate
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