Which substances corrode copper?​

The presence of oxidizing acids; heavy-metal salts, sulfur, and ammonia; and a number of sulfur and ammonia compounds can cause corrosion to set in. Water that comes from a well is much more likely to contain these materials and put copper lines in jeopardy—but it can occur in the civic water system as well.

Copper corrodes at insignificant rates when used in areas with unpolluted air, non-oxidizing acids, and water. However, it happens more rapidly with the presence of road salt, ammonia, sulfur, oxidizing acids

Acidic substances react with the surface of copper, causing it to tarnish and corrode almost instantly. This corrosion is highly soluble, leading to the presence of toxic copper salts in the food. This is why it is not recommended to use copper vessels for foods high in acidity, such as milk, wine, or vinegar.

B. Mixtures can be separated by physical means; compounds cannot.

For example a mixture of sand and water can be separated by physical means such as filtration, but a compound such as water cannot be separated by such physical means.