Q$7$: Which statements are not correct regarding solid lubricants and liquid lubricants? $($no explanation required$)$

a$)$ Solid lubricants can withstand much higher temperatures than liquid lubricants without breaking down or evaporating. This makes them suitable for applications where extreme heat is encountered, such as in aerospace and high$-$temperature manufacturing processes.

b$)$ Solid lubricants often exhibit lower friction coefficients compared to liquid lubricants. This can result in reduced wear and energy consumption.

c$)$ Solid lubricants do not leak or drip, keeping the application area clean. This is advantageous in industries like food processing, electronics, and optics.

d$)$ Liquid lubricants are generally more chemically stable and less susceptible to oxidation and degradation. They can provide long$-$lasting lubrication in harsh chemical environments.