One of the following is not a physical property of monosaccharides?

Analysis

The question asks us to identify which of the given options is not a physical property of monosaccharides. Monosaccharides (like glucose and fructose) are the simplest form of carbohydrates.

Concept Explanation

• Physical Properties: These are characteristics that can be observed or measured without changing the chemical identity of the substance. Common physical properties of monosaccharides include their solubility in water, their sweet taste, and their crystalline nature.
• Chemical Properties: These describe how a substance behaves during a chemical reaction (e.g., reacting with other substances, decomposition, or reduction).

Step-by-Step Evaluation

• Option A (Charring): When heated, monosaccharides undergo dehydration and decomposition, leaving behind carbon (charring). This is a chemical change/property.
• Option B (Solubility and Taste): Monosaccharides are polar molecules due to their hydroxyl (-OH) groups, making them highly soluble in water. They are also known for their sweet taste. These are classic physical properties.
• Option C (Exploration of metals): The exploration of metals (mining and metallurgy) involves geology, chemistry, and engineering. Monosaccharides have no role or relevance in the exploration or extraction of metals. This statement is factually incorrect in the context of chemistry.
• Option D (Reduction): The reduction of monosaccharides to sugar alcohols (like sorbitol) is a chemical reaction involving the conversion of the carbonyl group to a hydroxyl group.

Conclusion

While options A and D describe chemical properties rather than physical ones, Option C is the most distinct outlier because it is completely unrelated to the nature or behavior of monosaccharides. In the context of this JAMB question, the examiners are looking for the statement that is entirely false regarding the nature of these sugars.

Exam Tip

When you see a "Which of the following is NOT..." question, always look for the option that sounds completely out of place or scientifically irrelevant to the topic. Often, the "odd one out" is the correct answer.