Nanoparticles

Many properties of nanoparticles are significantly different than the corresponding bulk materials due to:
(a) Smaller band gap of nanoparticles compared to bulk.
(b) Higher heterogeneity of the nanoparticle solutions.
(c) Larger ratio of surface area to volume of the nanoparticles compared to the bulk.
(d) Smaller ratio of surface area to volume of the nanoparticles compared to the bulk.

Nanoparticles are of great scientific interest as they are, in effect, a bridge between bulk materials. A bulk material should have constant physical properties regardless of its size, but at the nano-scale size-dependent properties are often observed. Thus, the properties of materials change as their size approaches the nanoscale and as the percentage of the surface in relation to the percentage of the volume of a material becomes significant. For bulk materials larger than one micrometer (or micron), the percentage of the surface is insignificant in relation to the volume in the bulk of the material. The interesting and sometimes unexpected properties of nanoparticles are therefore largely due to the large surface area of the material, which dominates the contributions made by the small bulk of the material.

Answer:

Many properties of nano-particles are significantly different than the corresponding bulk material
because large ratio of surface area to volume of nono-particles in compare to the bulk.

Correct option is (c).