The solution of potassium chromate is treated with an excess of dilute nitric acid, the product formed are ;
1
Cr3+ and \(\rm Cr_2O^{2-}_7\)
2
\(\rm Cr_2O^{2-}_7\) and H2O
3
\(\rm Cr_2O^{2-}_7\) is reduced to +3 state or Cr
4
\(\rm Cr_2O^{2-}_7\) is oxidised to +7 state of Cr