- Silver chromate
Chembox new
Name = Silver chromate
ImageFile = Silver chromate.jpg
ImageName = Silver chromate
OtherNames =
Section1 = Chembox Identifiers
CASNo = 7784-01-2
Section2 = Chembox Properties
Formula = Ag2CrO4
MolarMass = 331.73 g/mol
Appearance = brown-red powder
Density = 5.625 g/cm3, solid
Solubility = 7.8x10-5 moldm-3
MeltingPt =Silver chromate (Ag2CrO4) is a brown-red
monoclinic crystal and is a chemical precursor to modernphotography . It can be formed by combining silver nitrate (AgNO3) and potassium chromate (K2CrO4).Laboratory use
The use of the compound itself in the laboratory is rather limited, although its formation is used to indicate the
endpoint in thetitration ofchloride withsilver nitrate .The solubility of silver chromate is slightly higher than that of silver chloride. So, in a mixture of both ions silver chloride will be formed. Only when no chloride is left, silver chromate will show its color.
Due to the color of the
chromate ion and theprecipitate ofsilver chloride already formed, prior to the endpoint the solution has a milky lemon yellow appearance. When closing in on the endpoint, additions of silver nitrate lead to steadily slower disappearing red colorations. When the red brownish color remains (with grayish spots of silver chloride in it) the endpoint of titration is reached.References
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