Preparation, Standardization and Estimation

  Ø   Apparatus:- ·          10 ml cylinder ·          Silica Crucible ·          Platinum Crucible   Ø   Reagents:- ·          Sulphuric Acid (AR Grade) ·          Nitric Acid (AR Grade) ·          Ammonium Molybdate 10% (w/v) Solution ·          Ammonium Nitrate (AR Grade)   Ø   Procedure:- Take approximately accurately 2 g sample in an accurately pre-weighted Silica Crucible. Then add sufficient amount Sulphuric Acid to wet the solution for digestion. Then digest very carefully in a fume hood. After complete digestion burn the crucible with sample at about 400°C in Muffle Furnace for about 2 hours. Then cool to room temperature. Then wash the residue through a Whatman 42 filter paper again and again until the filter paper becomes free of acid and store the filtrate for Phosphate test. Then after complete filtration take the filter paper with residue in a pre-weighted (C) Platinum crucible. Then burn that at about 800°C for approximately 2 hours. Then cool to

  Ø   Apparatus:- ·          250 ml conical flask ·          100 ml cylinder ·          50 ml burette   Ø   Reagents:- ·          0.1 (N) Sodium Hydroxide ·          Phenolphthalein   Indicator ·          Potassium Hydrogen Phthalate (A.R Grade)   Ø   Preparation of Solution:- ·          0.1 (N) Sodium Hydroxide:-   Weight accurately 4 g Sodium Hydroxide and dissolve in 1L DM water. ·          Phenolphthalein Indicator:- Dissolve 0.1 g of Phenolphthalein Indicator in 20 ml methyl alcohol and add sufficient water to produce 100 ml.   Ø   Procedure:- Take accurately about 0.4 g Potassium Hydrogen Phthalate (A.R Grade) in a conical flask. Add approximately 50 ml DM water and shake gently until dissolution. Then titrate it with 0.1 (N) Sodium Hydroxide solution with Phenolphthalein indicator until the colour changes from colourless to faint pink.   Ø   Calculation:-

  Ø   Apparatus:- ·          250 ml conical flask ·          100 ml cylinder ·          50 ml burette ·          10 ml pipette Ø   Reagents:- ·          0.1 (N) Potassium Dichromate Solution ·          Barium Diphenylamine Sulfonate (BDS) Indicator   ·          Sulphuric Acid (A.R. Grade) ·          Phosphoric Acid (A.R. Grade) Ø   Preparation of Solution:- ·          0.1 (N) Potassium Dichromate Solution:-   Weight accurately 4.903 g Potassium Dichromate and dissolve in 1L DM water. ·          Barium Diphenylamine Sulfonate (BDS) Indicator:- Mix thoroughly 1 g Barium Diphenylamine Sulfonate (BDS) Indicator and 50 ml Sulphuric Acid (A.R Grade) and make upto 100 ml with DM Water. Ø   Procedure:- Take 10 ml of the solution in a 250 ml conical flask. Then add 10 ml Sulphuric Acid (A.R. Grade) and 5 ml Phosphoric Acid (A.R. Grade) and 50 ml DM Water. Then titrate with 0.1 (N) Potassium Dichromate Solution using 5 -7 drops BDS Indicator Solution unti