CHEM CE 2006 Q4

2014-02-14 6:18 am

WHY only Ag+ reacts with Cl- to give a precipitate
AgCl???

WHY excess NaOH neutralized the HCl added before,
only Fe3+ gives precipitate
Fe(OH)3 ??

How to know which substance can react with other substance or not?

回答 (1)

Leo

2014-02-16 9:46 am

✔ 最佳答案

Ag+ does not only react with Cl-, but also Br- and I- to form creamy yellow and yellow precipitates respectively.

It also reacts with S2- and OH- to form black silver sulphide and silver oxide.

NaOH can react with Fe2+ to form dirty green iron(II) hydroxide, and with a variety of metal ions to form their insoluble hydroxides.

Cations usually form precipitate with anions of similar sizes and vice versa.
Ions of higher charges easily form precipitates with common ions of opposite charge.

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