Explain the following observations concerning oxidation: (a) A sheet of iron exp

Question

Explain the following observations concerning oxidation: (a) A sheet of iron exposed to dry air at room temperature does not oxidize to any appreciable degree. However, a sheet of iron heated red hot in dry air oxidizes fairly quickly. The oxide forms as a scale that flakes off of the surface (b) A small particle of iron that is freshly formed at room temperature and exposed to dry air (as, for example, in a grinding or machining operation) may actually burn, creating a spark. (c) A small particle of gold that is freshly formed and exposed to dry air will not burn, even if its temperature is relatively high.

Explanation / Answer

1) Rusting of iron is clearly a chemical reaction. As we know that rate of chemical reaction is directly proportional to the temperature, so heated iron will rust sooner when compared to iron at normal temperature.

2) Oxidising of iron is an exothermic reaction as in the case of rusting. When the iron particle is very small it will not be able to dissipate all the heat produced in reaction and as a result may burn with a flash.

3) Gold is inert when compared to iron due to its properties, so even if the temperature is high there will be very less chances of it getting oxidised and hence will not burn.

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.