Which of the following procedures cannot be performed on a hot plate and requires a Bunsen burner instead?

• A. Gently warming a beaker of water for solubility experiments
• B. Evaporating a salt solution in an evaporating dish
• C. Melting agar for microbiology media preparation
• D. Heating a crucible to red-hot temperatures for decomposition reactions

Answer: (D)

Verified step by step guidance

1. Understand the difference between a hot plate and a Bunsen burner in terms of the maximum temperature they can achieve. A hot plate provides controlled, moderate heating, while a Bunsen burner can reach much higher temperatures, including red-hot conditions.
2. Analyze each procedure to determine the required temperature: Gently warming water, evaporating a salt solution, and melting agar all require moderate heat, which a hot plate can provide safely and effectively.
3. Recognize that heating a crucible to red-hot temperatures for decomposition reactions requires very high heat, often exceeding the capabilities of a hot plate.
4. Recall that a Bunsen burner produces an open flame capable of reaching temperatures sufficient to heat a crucible to red-hot conditions, which is necessary for certain decomposition reactions.
5. Conclude that the procedure requiring heating a crucible to red-hot temperatures cannot be performed on a hot plate and must be done using a Bunsen burner.