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Question:

Why aluminum reacts slowly with dilute acids?

Can someone please explained what aluminum reacts slowly with dilute acided?Thank you!

Answer:

Aluminum metal is not very reactive because of the passivating layer of aluminum oxide, Al2O3, on the surface of the metal. The oxide coating can be dissolved by solutions which are either very acidic or very basic. ======== Follow up ======== Whoa, Nellie. Back the boat up. The oxide coating on aluminum comes from oxygen in the air and covers the surface of the aluminum long before it landed in the acid solution. The dissolved oxygen in the acid solution is NOT the reason for oxygen combining with aluminum. The pH of the solution has little influence on the amount of dissolved oxygen. The partial pressure of O2 above the water and the temperature of the water are much more important to the amount of dissolved oxygen.
Firstly, dilute acids are weaker than concentrated acids. This slows the rate of reaction. Secondly, Aluminium is less reactive than the Group 1 and Group 2 metals, which slows the rate of reaction. It is less reactive because it has to form 3+ ions which is more draining than forming 1+ or 2+ ions. Thirdly, Aluminium oxidises well in air but, unlike rust, this oxide sticks to the pure aluminium, forming a protective layer.
rethink your question, is non sensical at this point.

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