Question

why K2Cr2O7 shows yellow colour?​

Answer 1

Answer:

because of chromium oxide

Answer 2

Answer:

The color change depends on the changes in the pH of the solution. Dichromate salts contain the dichromate anion, Cr2O72- and chromate salts contain chromate anion, CrO42−. When an alkali is added to an orange red solution of dichromate, an yellow solution is obtained due to the formation of chromate ions.