Silver

Chemical reactions




Reaction of silver with acids


Silver metal dissolves in hot concentrated sulphuric acid.


Silver dissolves in dilute nitric acid, HNO3 [8].

3 Ag(s) + 4 HNO3(aq) AgNO3(aq) + NO(g) + 2 H2O(l)


Reaction of silver with air


Silver metal is stable in clean air under normal conditions.


Reaction of silver with ammonia


Ammonia precipitates Ag+ as brown/black oxide.

2 Ag+(aq) + 2 NH3(aq) + H2O(l) Ag2O(s) [brown/black] + 2 NH4+(aq)

In excess, ammonia dissolves the precipitate, forming a diamine silver complex.

Ag2O(s) + 4 NH3(aq) + H2O(l) 2 [Ag(NH3)2]+(aq) + 2 OH(aq)


Reaction of silver with cyanide


Ag+ forms complexes with cyanide.

Ag+(aq) + 2 CN(aq) [Ag(CN)2](aq)


Reaction of silver with halides


Ag+ is precipitated by halides. The precipitates can be dissolved again in concentrated halides.

Ag+(aq) + Cl(aq) AgCl(s) [white]
AgCl(s) + Cl(aq) [AgCl2](aq) + Cl(aq) [AgCl3]2−(aq) + Cl(aq) [AgCl4]3−(aq)

Ag+(aq) + Br(aq) AgBr(s) [light yellow]
AgBr(s) + Br(aq) [AgBr2](aq) + Br(aq) [AgBr3]2−(aq) + Br(aq) [AgBr4]3−(aq)

Ag+(aq) + I(aq) AgI(s) [yellow]
AgI(s) + I(aq) [AgI2](aq) + I(aq) [AgI3]2−(aq) + I(aq) [AgI4]3−(aq)


Reaction of silver with hydroxide


Hydroxide ions precipitates Ag+ as brown/black oxide.

2 Ag+(aq) + 2 OH(aq) Ag2O(s) [brown/black] + H2O(l)


Reaction of silver with sulfide


Ag+ is precipitated by hydrogensulfide in 0.4M HNO3(aq).

2 Ag+(aq) + H2S(aq) Ag2S(s) [black] + 2 H+(aq)


Reaction of silver with the thiosulfate


Ag+ forms complexes with thiosulfate.

Ag+(aq) + 2 S2O32−(aq) Ag(S2O3)23−(aq)

The process is used for removing AgBr(s) in photographic fixing.


Reaction of silver with water


Silver does not react with clean water.


Quantitative analysis


Method 3500-Ag C Inductively Coupled Plasma Method [2]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.

Method limit of detection in water = 0.003 mg/L
Method limit of detection in soil = 0.10 mg/kg