Assay of Ammonium Chloride

 

Aim: Carry out the assay pf Ammonium chloride by modified acid base titration

Principle: Modified Acid base back titrated by modified acid base titration where the formaldehyde react with ammonium chloride and converted them to Hexsamethelin tetramin and liberate equivalent amount of HCl. the liberated HCl is titrated against standard NaOH using phenlopthalin indicator.The end point colour changes will be the colorless to pale pink/pink

 

 

Procedure:

Preparation and standardization of 0.1N NaOH

• Dissolve around 0.4g of NaOH in disstilled water and make up the volume 100ml by adding water which will produce approximately 0.1N NaOH.
• 0.63g of Oxalic acid are dissolved in water and make up the volume  100ml by adding water which will produce 0.1N oxalic acid.
• Pipette out 10ml  of 0.1N oxalic acid in a clean conical flask add  10ml of water and add 2 drops of phenlopthalein indicator
• Titrate the solution against prepared 0.1N NaOH until the appearance of pink color.
• Repeat the procedure take the average reading and calculate exact normality of NaOH by using the formula N₁V_1(NaOH) =N₂V_{2(Oxalic acid)}

Assay of Ammonium Chloride:

•  Dissolve the given sample in volumetric flask in volumetric flask by adding water. Pipette out 20ml of the solution in a clean conical flask,
• Add 20ml of previously neutralize formaldehyde solution and 2drops of Phenlopthalein indicator
• Titrate the solution against standard 0.1N NaOH until the aappearance of pale pink color
• Repeat the procedure take the average reading and calculate the amount of sample present by using following formula.

Observation and Calculation :

Standardization of 0.1N Sodium Hydroxide

Burette            :0.1N NaOH 

Conical Flask  : 10ml 0.1N Oxalic acid +2drops Indicator

Indicator             : Colorless to pale pink 

Oxalic acid Vs 0.1N Sodium Hydroxide 

Sl No.	Volume of Oxalic Acid (ml)	Volume Of NaOH (0.1N)		Volume of NaOH consumed (ml)	Color Change
		Initial (Ml)	Final (Ml)

Calculation:

N₁V_1(NaOH) =N₂V_{2(Oxalic acid)}

Assay of Ammonium Chloride:

Burette               :20ml Sample

Conical Sample : 20ml previously neutralized Formaldehyde (Neutralized with phenlopthalein)

Indicator            : Phenlopthalin

End Point           : Colorless to pale pink

Oxalic acid vs 0.1N sodium Hydroxide 

Sl No.	Volume of Sample (ml)	Volume Of NaOH (0.1N)		Volume of NaOH consumed (ml)	Color Change
		Initial (Ml)	Final (Ml)

Calculation :

IP Factor

Each ml of 0.1N NaOH is equivalent to 0.005349g of NH₄Cl

Amount of sample present in 100ml of the solution =

Report :

The percentage purity of the given sample of ammonium chloride was found to be ____%