What are possible source of error for rusting of a nail​

A nail can rust when exposed to oxygen. the molecules of iron on the surface of the nail exchange atoms with the oxygen in the air and produce a new substance, the reddish brown ferrous oxide i.e rust.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".