Un morceau vs. un bout: any difference?

1.9 Part 2: Making Things Really Clear with Articles Is un morceau and un bout interchangeable? They both mean a piece. If not can someone please give me an example of a sentence when to use un morceau and un bout. Side bar: I read someplace else where that they used de l'ail. Shouldn't it be d'ail since ail is a masculine word?

Bonjour M L, 'Morceau' does indeed mean piece as does 'bout' but 'bout' is often more specifically used to refer to a piece at the end of something else. For example, the crust (or end piece) of a loaf of bread - "le bout du pain". However, you couldn't use 'bout' if you were referring to a cake for example because it has no distinguishable end. In this case you would use 'morceau'. I hope this helps and keep up the good work! - Marie-Claire

What is the answer to the side bar above? Is it d'ail or de l'ail?