Final answer:
The experiment could go wrong due to the contamination of reactants, which alters the outcome by introducing unintended substances that can cause unexpected results. The correct option is b.
Step-by-step explanation:
When conducting an experiment like the formation of copper metal, one example where the experiment could go wrong is contamination of reactants. Contamination can alter the outcome of the chemical reaction by introducing unintended substances, which may react differently and lead to unexpected results. This is crucial because the purity of the reactants in a chemical experiment greatly influences the validity and reproducibility of the results.
Other potential issues in a chemical experiment can include high temperature causing an explosion and increased pressure leading to equipment failure. It is important to follow safety guidelines, such as never eating or drinking in the lab, cleaning materials properly, and being cautious when using flames or heat plates to prevent such accidents.
Hence, Option b is correct.