Reaction with alkali

2009-09-22 1:32 am

I'd like to ask why silver ion when added to alkali gives AgO but not AgOH?

For other metals ions like calcium, aluminium, and even copper can make hydroxide ion when added to alkali, e.g.

Ca2+ + 2OH- --> Ca(OH)2 + H2O
Al3+ + 3OH- --> Al(OH)3 + H2O
Cu2+ + 2OH- --> Cu(OH)2 + H2O

Ag+ + OH --> AgO + H2O?????

Please explain why there is such a difference between Ag and the other metals!!!

Thanks a lot!

回答 (1)

老爺子

2009-09-22 1:56 am

✔ 最佳答案

Silver hydroxide is described as a white precipitate in some books. However, silver hydroxide is very unstable and is decomposed immediately to dark precipitation of silver oxide and water.

Therefore, it can be thought that in the reaction between silver ion and hydroxide ion, the silver hydroxide formed is decomposed to silver oxide and water immediately.
2Ag+(aq) + 2OH-(aq) → 2[AgOH](very unstable)
2[AgOH] → Ag2O(s) + H2O(l)

There is no silver hydroxide that can be observed. Therefore, the equation is written as:
2Ag+(aq) + 2OH-(aq) → Ag2O(s) + H2O(l)

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