What are the differences in the reactivity of "bromoethane", and "2-bromopentane"?

Well, $\text{bromoethane}$ should be more reactive for a reaction with a associative mechanism...........
And $\text{2-bromopentane}$ should be more reactive in a dissociative scenario.
So bromoethane should be liable to undergo reaction with, say, $N a O H$, in an ${S}_{N} 2$ mechanism, to form ethyl alcohol and sodium bromide. Under the same conditions, $\text{2-bromopentane}$ might be liable to undergo elimination to give $\text{2-pentylene}$.