【Daily Question No. 138】May 10, 2016: +2 wealth for participation, +3 wealth for a correct answer
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Copperware in long-term contact with which of the following seasonings will produce toxic patina? (D) A. Soy sauce B. Sichuan pepper powder C. Monosodium glutamate D. Vinegar. Reply with the answer you think is correct; participating in the quiz earns +2 wealth points. Getting all answers right adds another +3 wealth points, and additional rewards will be given for providing detailed explanations or analyses of the questions and answers. Note: We will close this post after 24 hours. Outside of answering questions, I hope everyone can share their suggestions~ Feel free to express any ideas regarding the daily question or anything else~
The role of vinegar is to provide an acidic environment; in such an environment, copper is easily oxidized by the oxygen in the air, resulting in the formation of basic copper carbonate (what we commonly refer to as patina). If the copper material is impure and contains other contaminants, copper and these contaminants form a galvanic cell, with vinegar acting as the electrolyte solution, which facilitates the reaction. In a vacuum, pure copper does not react with vinegar!
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