Question

The surface area-to-volume ratio of nanoparticles:

• A. Remains constant regardless of size
• B. Decreases with decreasing particle size
• C. Increases with decreasing particle size
• D. Has no impact on chemical reactivity

Hint:

The surface area-to-volume ratio of nanoparticles increases as their size decreases. This increase in surface area enhances their reactivity and makes nanoparticles more effective in catalysis and other chemical processes.
Understanding this ratio is key to leveraging the unique properties of nanomaterials.

Answer 1

The Correct Option is C

The surface area-to-volume ratio is a critical factor in determining the properties and behavior of nanoparticles, especially when compared to bulk materials. Let's analyze the options in detail.
Step 1: Understand the concept of surface area-to-volume ratio
The surface area-to-volume ratio (SA:V) is the ratio of the surface area of an object to its volume. In nanoparticles, this ratio is significant because it determines how much of the material is exposed to the environment. Higher surface area leads to more active sites for chemical reactions. As the particle size decreases, the surface area increases relative to the volume.
Step 2: Analyze Option A - Remains constant regardless of size
The surface area-to-volume ratio does not remain constant as the size of the nanoparticle changes. In fact, this ratio changes with size and is particularly large for small nanoparticles.
Thus, option A is incorrect.
Step 3: Analyze Option B - Decreases with decreasing particle size
As particle size decreases, the surface area-to-volume ratio actually increases, not decreases. Smaller nanoparticles have a higher surface area relative to their volume, making them more reactive.
Thus, option B is incorrect.
Step 4: Analyze Option C - Increases with decreasing particle size
This is the correct option. As nanoparticles become smaller, the surface area increases disproportionately compared to the volume. This higher surface area-to-volume ratio contributes to increased reactivity and other unique properties that nanoparticles exhibit.
Thus, option C is correct.
Step 5: Analyze Option D - Has no impact on chemical reactivity
The surface area-to-volume ratio has a significant impact on chemical reactivity. A larger surface area increases the number of reactive sites on the nanoparticle, which can enhance reactivity in chemical processes. Therefore, option D is incorrect.
Step 6: Conclusion
The surface area-to-volume ratio increases as the size of nanoparticles decreases, making them more reactive due to the increased surface area. Therefore, the correct answer is option C.