Question

3. Why do we start our last step reacting with granular Zinc, and then move to mossy zinc? What error are we trying to avoid?

Answer 1

Answer:

Zinc metal dust can be a dangerous fire risk; may form explosive mixture with air. If allowed to get damp in a confined bottle, heat will be generated and the mixture may even ignite; cases are known where bottles have exploded under pressure. Keep this product dry!

Explanation:

SPECIAL HAZARD ALERT: Granular zinc is often used in a classic lab experiment to turn copper pennies into “silver” and then “gold.” See the Gold Rush Chemical Demonstration Kit (Catalog No. AP8895). Do not use sodium hydroxide in this reaction—the leftover basic zinc residue is a fire hazard. Call or write us to obtain a complimentary copy of a revised procedure for this demonstration using granular zinc and zinc chloride. Request Publication No. 10991.