1.

In the titratin of Fe^(2+) ions with KMnO_(4) in acidic medium, why dilute H_(2)SO_(4) is used and not dilute HCl ?

Answer»

Solution :`KMnO_(4)` in presence of dilute `H_(2)SO_(4)` acts as oxidizing agent and oxygen produced oxidizes FERROUS salt to FERRIC salt
`2KMnO_(4) + 3H_(2)SO_(4) rarr K_(2)SO_(4) + 2MnSO_(4) + 3H_(2)O +5(O)`
`2FeSO_(4) + H_(2)SO_(4) + (O)rarr Fe_(2)(SO_(4))_(3) + H_(2) O ] xx 5`
`bar ( 2KMnO_(4) + 8 H_(2) SO_(4)+ 10 FeSO_(4) rarr K_(2)SO_(4)2MnSO_(4) + 5Fe_(2)(SO_(4))_(3) + 8 H_(2)O)`
`KMnO_(4)`in presence of dilute HCl also acts as oxidizing agent but oxygen produced is usedup partly for OXIDATION of HCl
`2KMnO_(4) + 4HCl rarr 2KCl+ 2MnCl_(2) + 2H_(2)O + 6 (O)`
`2HCL +(O) rarr H_(2)O+ Cl_(2)`


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