Exercise 45. Zinc Hyposulfite

Into a 500-cc. Erlenmeyer flask put enough granulated zinc to cover the bottom. Pour over this about 150 cc. of absolute alcohol and provide the flask with a two-hole stopper. Through one hole insert a delivery tube dipping under the alcohol and through the other an exit tube 

The salt is a powerful reducing agent and has been employed to reduce indigo to a colorless base. It is difficult to preserve unchanged and should be sealed in a bottle after displacing the air with coal gas. 

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