Sulfurous Acid → Sulfurous acid, calcium salt (2:1)

Participants

Reaction Steps

Fifty grams of the above material was suspended in one liter of sulfurous acid solution containing 62.5 grams of sulfur dioxide. The molar ratio of sulfur dioxide to calcium in the original mixture was 3.00 or 50 percent in excess of that required to form calcium bisulfite. The mixture was held in a flask stoppered with a water trap tube at 20° C for 2 hours using intermittent agitation. At the end of the period the solution contained 54.4 grams of total sulfur dioxide or 87 percent of that originally present. The chitin was collected on a filter, washed and analyzed for residual calcium carbonate. It contained 0.81 grams or 2.5 percent of that originally present in the deproteinized shell. Demineralization was thus 97.5 percent complete and sulfur dioxide evolved with carbon dioxide through the trap tube was 13 percent of that originally present or 39 percent of the excess employed.

Provenance & Evidence