Which of the following items used in a typical staining exercise in microbiology are potentially dangerous to the student?

• A. Glass microscope slide
• B. Bunsen burner
• C. Crystal violet stain
• D. Distilled water

Answer: (B)

Verified step by step guidance

1. Identify each item used in a typical staining exercise and consider its potential hazards based on its physical and chemical properties.
2. Evaluate the glass microscope slide: it is generally safe but can cause injury if broken, so handle with care but it is not chemically dangerous.
3. Consider the Bunsen burner: it produces an open flame and heat, which can cause burns or start fires, making it potentially dangerous if not used properly.
4. Assess the crystal violet stain: it is a chemical dye that can be toxic or irritating if ingested or if it comes into contact with skin or eyes, so it requires careful handling.
5. Review distilled water: it is pure water and non-toxic, posing no danger in typical staining procedures.
6. Conclude that among the listed items, the Bunsen burner is the most immediately dangerous due to the open flame, while crystal violet also requires caution due to its chemical nature.