Question

Why is graphite used as a dry lubricant in machinery?
a.) Each carbon atom undergoes \[s{{p}^{3}}\] hybridization in graphite
b.) Graphite has layered structure and it cleaves between the layers and therefore it is very
soft and slippery
c.) Graphite is a non-conductor of electricity
d.) Graphite has two sigma bonds and two pi bonds

Answer 1

Hint: Graphite, on account of its impossible to miss microstructure made out of hexagonal planes of hybridized \[s{{p}^{2}}-s{{p}^{3}}\] carbon bonds, has awesome greasing up properties. Interlayer bonds are powerless so the material will in general chip without any problem.

Complete answer:
The single pieces are slight (to the furthest reaches of being graphene) and can without much of a stretch position themselves between two surfaces in complementary movement producing a circumstance of three-body wear (surface-graphite-surface) with extremely low coefficients of friction. It is utilized, as an ointment, chiefly in two different ways.
Powders:
Graphite powders are included in advertising a strong ointment in greasing up sprays and in modern oils utilized for specialized applications (for hot manufacturing/stepping and to keep oil in mechanical apparatuses, for instance). This is generally the most incessant use. Dealing with is simple, ease is high, they are simply grimy and will in general stick to anything. Simple to wash away in the cleanser.
Bushings:
Bronze bushings where just dry grease is allowed are as often as possible altered with graphite additions to make bronze-graphite composite bushings as the picture underneath. These assurances have a low coefficient of rubbing without the utilization of oils and other fluid greases.

The correct answer is B.

Note: Another intriguing application is to add it to the powders from which sintered bronze bushings are created. There are powder metallurgy products utilized any place there are pivoting or swaying shafts. In the event that the mechanical forces aren't too requesting it can likewise be utilized straightforwardly as a sintered graphite bushing.