Analytical Procedures - SO₂ in Weak Acid
February 12, 2002

Introduction Equipment Reagents Procedure Calculations

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Introduction

The sulphur dioxide is oxidized by a iodine solution, with starch as indicator.

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Equipment

• Burette
• 50 ml flask
• 250 ml  Erlenmeyer flask

Reagents

 

• Potassium iodide

• Iodine solution 0.1 N  (Dissolve  12.7 g of Iodine bi-sublimate, and 40 g of potassium iodide in 1 liter of water.  Let the solution stabilize for a few days in a dark place and then determine the standardisation factor with Na₂S₂O₃).

Procedure

Draw 50 ml of decanted solution of scrubber purge, add few drops of starch indicator solution and titre with iodine solution 0.1 N.

Calculations

 SO₂ [g/l]    =        V₁  x  0.1   x  F  x  0.032  x  1000  /  V

 where:

V₁        = ml of Iodine used
F          = corrector factor of Iodine 0.1 N solution
V          = ml of scrubber purge solution used