Final answer:
Option C: The incorrect statement about the properties of nanomaterials due to nano size is that they possess lower thermal and mechanical stabilities, as they often have higher stabilities and strength.
Step-by-step explanation:
The student asked which of the following is incorrect about the properties of nanomaterial due to nano size: higher electrical conductivity, higher surface energy, lower thermal and mechanical stabilities, or an increase in surface area. The incorrect statement is that nanomaterials have lower thermal and mechanical stabilities. Typically, materials at the nanoscale often show higher strength and thermal stability due to their greater surface area to volume ratio and the fact that more atoms are at grain boundaries or surface sites where they are more tightly bound. Moreover, effects like quantum confinement can enhance certain material properties at the nanoscale. Nanomaterials tend to have higher electrical conductivity and surface energy, as well as increased surface area.
Nanomaterials generally do have higher electrical conductivity, particularly when materials, such as semiconductors, are at the nanoscale, since the confinement of electrons can change their electrical properties. Resistance of semiconductors decreases with increasing temperature, making them better conductors due to the increase in free charges that can carry current. Additionally, they also exhibit higher surface energy because of the increased proportion of atoms at the surface, which can lead to more reactive or energetically favorable interactions. An increase in surface area is also a correct property attributable to nanoscale materials. This increased surface area can have various applications, from catalysis to enhanced reactivity.