Saturated hydrocarbons with what length of carbon chain are the best lubricants?
1–2
5–8
17–35
more than 35

The best lubricant have around 17-35 saturated hydrocarbons. Lubricants can either be liquid (oils) or solid (grease). Oils typically have 15-20 carbon atom chains, while grease has 20-35 carbon atoms chains. This means that both lubricant types fall under the range 17-37.

Because it is held together by weak forces so no much energy is needed to break the bond