Question 4 of 15 Aluminium appears unreactive. This is because it has a layer of what covering its surface? Enter your answer

## Step1: Aluminium indeed would seem unreactive due to the ongoing contact with air. When in constant contact with the atmospheric air, aluminium undergoes an oxidation reaction, creating a protective layer on the surface.## Step2:This oxidation reaction forms a layer of "Aluminium Oxide". This oxide layer is a hard inert material that adheres tightly to the aluminium that produced it, and consequently lessens direct exposure to air or other substances, hence preventing further reaction.### Formula: The reaction of Oxygen (O) present in the atmosphere with Aluminium (Al) could be represented as: This equation depicts 4 moles of Aluminium reacting with 3 moles of Oxygen to form 2 moles of Aluminium Oxide.