Practicals : Why conc H2SO4 is added to Mohr salt before making its solution in distilled and dilute H2SO4 before titration begins?

Open in App

Solution

Mohr salt is FeSO₄(NH₄)₂SO_4.6H₂O, in which iron exist in +2 oxidation state.
Hence to prevent its oxidation to Fe^3+,concentrated sulphuric acid is used.
When Mohr salt is titrated against KMnO₄ ,Fe²⁺is oxidised to Fe^3+. and if it is already oxidised then error would be there and result will not be accurate.
Also, when it is titrated, dilute sulphuric acid is added during the titration, as reaction proceeds well in acidic medium. also KMnO₄ acts as good oxidising agent in acidic medium.
The overall reaction of the titration is:
2KMnO₄+ 10FeSO₄+ 8H₂SO₄_$\to$K₂SO₄+2MnSO₄ + 5Fe₂(SO₄)₃ + 8H₂O

Suggest Corrections

Similar questions

Why is water not added to concentrated $H_{2} S O_{4}$ in order to dilute it ?

22.7 mL

\frac{N}{10} N a_{2} C O_{3}

10.2 mL

H_{2} S O_{4}

400 mL

H_{2} S O_{4}

\frac{N}{10}

N a_{2} C O_{3}

H_{2} S O_{4}

H_{2} S O_{4}

22.7 mL

\frac{N}{10} N a_{2} C O_{3}

10.2 mL

H_{2} S O_{4}

400 mL

H_{2} S O_{4}

\frac{N}{10}

Join BYJU'S Learning Program