xplain why in 1-2 lines (6)(a) Diamond is hard, but graphite is soft.(b) (100) plane is absent in the X-ray diffraction pattern of the BCC structure.(c) There is no Face Centered Tetragonal lattice.(d) Larger size anode has less corrosion.(e) A regular 2-D pentagon lattice is not possible.(f) An optical microscope cannot detect nanomaterials ( size < 100 nm).

(a) Diamond is hard because it has a rigid tetrahedral network where each carbon atom is bonded to four other carbon atoms. Graphite is soft because it consists of layers of carbon atoms with weak interlayer bonding, allowing the layers to slide over each other.

(b) The (100) plane is absent in the X-ray diffraction pattern of the BCC structure because the structure factor for this plane is zero, meaning that the scattered X-ray waves from the atoms on this plane destructively interfere and cancel each other out.

(c) There is no Face Centered Tetragonal lattice because the face centered tetragonal unit cell is not one of the 14 Bravais lattices, which are the only possible unique arrangements of points in three-dimensional space.

(d) Larger size anode has less corrosion because the rate of corrosion is inversely proportional to the surface area of the anode. A larger anode has a larger surface area, which means a lower corrosion rate.

(e) A regular 2-D pentagon lattice is not possible because regular pentagons cannot tessellate, or fill a plane, without leaving gaps.

(f) An optical microscope cannot detect nanomaterials because the resolution of an optical microscope is limited by the wavelength of light, which is larger than the size of nanomaterials.