A ketone will give a negative result because it cannot be oxidized easily.

Steel wool oxidizes easily because it offers a large surface area for attack.

Because it is easily oxidized it must be kept under vacuum.

More so than thiophenol, benzeneselenol is easily oxidized by air.

It is easily oxidized to nitrogen dioxide by air.

Motor oils have good boundary protection, but they are not meant to be exposed to open air and oxidize easily.

Due to the electron-rich nature of indole, it is easily oxidized.

Terbium easily oxidizes, and is therefore used in its elemental form specifically for research.

It is a soft, silvery, ductile metal which easily oxidizes in air.

Since Mg is easily oxidized, the amount of oxidation coating the strip can also have some effect.