Question

What are the conditions necessary for rusting to take place ?In what way, oiling and greasing help in preventing the rusting?

Answer 1

Hey MATE!

The necessary conditions for rusting are :

1) Presence of moisture.

2) Prsence of oxygen.


Oiling and rusting prevent rusting by developing a layer over the surface of the object making it difficult to come in contact with the both.

Hope it helps
Pls mark it brainliest #))

Answer 2

Rust prevention

Stainless steel is an iron alloy that does not rust. It is used to make kitchen sinks, for example.

There are several ways to prevent iron and steel rusting. Some of these work because they stop oxygen or water reaching the surface of the metal:

oiling - for example bicycle chains

greasing - for example nut and bolts

painting - for example car body panels

Iron and steel objects may also be covered with a layer of metal. Food cans, for example, are plated with a thin layer of tin.



‘Tin’ cans are made of steel coated with a thin layer of tin metal

Galvanising

Galvanising is a method of rust prevention. The iron or steel object is coated in a thin layer of zinc. This stops oxygen and water reaching the metal underneath - but the zinc also acts as a sacrificial metal. Zinc is more reactive than iron, so it oxidises in preference to the iron object.

Sacrificial protection – Higher tier

The reactivity series lists metals in order of how reactive they are.



The reactivity series for some metals

Magnesium and zinc are often used as sacrificial metals. They are more reactive than iron and lose their electrons in preference to iron.

Although tin is used to coat steel cans, it does not act as a sacrificial metal. Instead, it acts only as a barrier to stop air and water reaching the surface of the iron or steel. The tin layer may actually make rusting happen faster if it gets scratched, because then iron loses electrons in preference to tin.