in ferrous sulphate the oxidation no. of iron is +2 after reaction it changes to +3.this is oxidation reaction in which oxidising agent is K2Cr2O7

Oxidation-Reduction Reaction Overview
In the reaction between ferrous sulfate (FeSO4) and acidified potassium dichromate (K2Cr2O7), a redox reaction occurs where oxidation and reduction take place simultaneously.
Oxidation State Changes
- The oxidation state of chromium in potassium dichromate (K2Cr2O7) is +6.
- During the reaction, chromium is reduced to an oxidation state of +3.
Role of Ferrous Sulfate
- Ferrous sulfate (FeSO4) acts as a reducing agent.
- It gets oxidized from Fe(II) to Fe(III), increasing its oxidation state from +2 to +3.
Overall Reaction
- The balanced chemical equation for the reaction is:
6 FeSO4 + K2Cr2O7 + 7 H2SO4 → 6 Fe2(SO4)3 + Cr2(SO4)3 + K2SO4 + 7 H2O
- In this equation, we see the conversion of Fe(II) to Fe(III) and Cr(VI) to Cr(III).
Significance of Oxidation State Change
- The change in chromium’s oxidation state signifies its ability to accept electrons, which is a critical aspect of redox chemistry.
- The reduction of potassium dichromate is often used as an analytical method to determine the concentration of reducing agents in a solution.
Conclusion
- In summary, during the reaction between ferrous sulfate and acidified potassium dichromate, the oxidation state of chromium changes from +6 to +3, illustrating a clear example of redox chemistry in action.