sarcrficial protection(urgent)

2010-09-18 4:13 am

I know that iron can be protected by attaching a more reactive metal like Zn to it as it loses electrons more readily. But why a less reactive metal can speed up rusting when attached to iron? Even though iron loses electrons in preference to that metal, why the speed is even faster than without the present of a less reactive metal?

thanks

更新1:

2. My book states that putting iron nail into sodium chloride can speeds up rusting because it increases the electrical conductivity, but what is the relation between this and rusting? 3. Why a sharply pointed region of iron nail does rust most readily?

更新2:

Do=id you mean that originally both metals corrode, but since iron is more reactive, besides its own rusting, it also loses electrons to the less reactive metal, thus speesing up rusting?

回答 (1)

[匿名]

2010-09-18 8:37 am

✔ 最佳答案

1. U Can treat it like this:
originally, only iron carries out rusting
however, with a less reactive metal, iron loses electrons more preferably, so it loses the electrons for the less reactive metal also. therefore, rust faster.

2. when electrical conductivity increases, the ions and electrons flow faster. as rusting is a process in which iron loses electrons, rusting occurs faster.

3. a sharp area has a larger area to volume ratio, so occurs rusting more easily

2010-09-19 00:30:57 補充：
yes the less reactive metal is being oxidized in room conditions also

參考: me, me

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