ANN 111: Principles of Animal Nutrition and Feed Technology (2+1)

PRINCIPLE

• The calcium in the soluble ash is precipitated as calcium oxalate by the addition of saturated solution of Ammonium oxalate.  This is then dissolved in dilute sulphuric acid.

            CaC₂O₄ + H₂SO₄ ®CaSO₄ + H₂C₂O₄ (Oxalic acid)

            (Oxalic acid is a reducing agent)

• The calcium is determined volumetrically by titrating the solution with standard KMnO₄.

2KMnO₄ + 3H₂SO₄ + 5H₂C₂O₄ ® 2MnSO₄ + K₂SO₄ + 10CO₂ + 8H₂O