Iron & Gold Corrosion?

Question

why in acid solution gold is not corroded??
why in acid solution iron is hardly corroded??

Answer 1

Gold is a non-corrosive element (no free electrons in relation to the number of protons in the nucleus), in that it will not combine with oxygen to produce gold-oxide (corrosion), and it is one of the best conductors of electricity of all the elements. Which is why gold plating is selected for use in electronic circuits where corrosion can be a problem.

Iron in an acid solution hardly corrodes because the acid solution may contain very little oxygen. Put the iron in an oxygen-rich environment and the corrosion will increase dramatically in the form of iron-oxide (rust). This is why pure iron is not a good choice where corrosion could be a problem, unless measures are taken to prevent or minimize the corrosive properties of the surrounding environment.

As an example, when ductile iron is used for water pipes, it is necessary to set up corrosion-control electrical systems and to isolate the ductile iron pipes where they connect to other pipes that could induce an electrolytic flow, and they are coated with mortar to prevent contact with the soil. Monitoring stations are set up to test the pipe and monitor the amount of electrolysis in the pipe.

Answer 2

Pull the iron out into the air and it will start oxidizing corrosion is electrons escaping from the metal. Gold has non corrosion properties steel & iron really rusts out.