Sodium and potassium dichromates are strong oxidising agents;
the sodium salt has a greater solubility in water and is extensively
used as an oxidising agent in organic chemistry Potassium dichromate
is used as a primary standard in volumetric analysis In acidic solution,
its oxidising action can be represented as follows:
Cr2O7
2– + 14H
+ + 6e
– ® 2Cr
3+ + 7H2O (E
o = 1 33V)
Thus, acidified potassium dichromate will oxidise iodides to iodine,
sulphides to sulphur, tin(II) to tin(IV) and iron(II) salts to iron(III)