Is lead chromate soluble in water

Potassium chromate K2CrO4 

 
Teflon closure
 
 
 

 
Yellow
Crystals
molar mass 194.191 g / mol
  



AGW n / a, carcinogenic substance
Melting point + 974 ° C
density 2.73 g / cm3   
Water solubility 
100g H2O dissolve 63.68 g at 20 ° C
Pictograms  
   
GHS 07
GHS 08
GHS 09
    
danger
 
Hazard classes + category   
Corrosive / irritant effect. on the skin 1B
Serious eye damage / irritation 2
Skin sensitization 1
Germ cell mutagenicity 1B
Carcinogenicity inhalation 1B
Spec. Target organ tox. e. Resp. 3rd
Water vessel. acute / chronic 1
HP rates (see note)     
  
H 315, 317, 319, 335, 340, 350i, 410
P 261, 273, 280.1-3 + 5 + 7, 302 + 352, 305 + 351 + 338, 308 + 313
  
disposal special instructions
 
print a labelGerman nameEnglish name
CAS7789-00-6Potassium chromatePotassium chromate
     
Note for schools: Potassium chromate (and also sodium chromate) is carcinogenicity in German schools due to its assignment to the hazard classes and Germ cell mutagenicity, Category 1B prohibited. It is recommended not to use this material in schools in Switzerland or in other countries either.
    
  
properties 
   
Potassium chromate forms intensely yellow crystals that do not attract water and are not hygroscopic. When heated to over 670 ° C, potassium chromate changes to a red, hexagonal modification. When mixed with flammable substances, easily flammable mixtures are formed. However, it is not quite as oxidizing as potassium dichromate. The toxicity is also somewhat lower, but it is still a very dangerous substance for health.
   



An external comparison of two toxic chromates

   

 
Potassium chromate serves as a detection reagent for lead ions. If an aqueous potassium chromate solution is added to an aqueous solution of lead (II) nitrate or lead (II) acetate, an intense yellow lead (II) chromate precipitates:
  
Pb2+ + CrO42-  PbCrO4

The lead (II) chromate was previously used as a yellow pigment called "Paris Yellow". However, due to its toxicity, it is no longer produced for paints today.

   

Enlarge image

Add a potassium chromate solution to a soluble one
Lead salt solution, yellow lead chromate precipitates.
     
   
Manufacturing 
   
Production takes place in the laboratory from aqueous potassium dichromate solution and potassium hydroxide solution. By raising the pH value with the help of the potassium hydroxide solution, the equilibrium of the reaction is shifted to the right, so that the potassium chromate is increased:
   
H2O + K2Cr2O+ 2 KOH 2 K2CrO4 + 2 H.2O
    
   
use 

Potassium chromate used to be used as a mordant in dyeing and for the preparation of lead chromate. It was also used in printing and ink making. It is used as an indicator in dimensional analysis. Since sodium chromate is cheaper to manufacture, this salt largely replaces potassium chromate today.