In which of the following redox reaction precipitate is not formed?

Options

A. `Cr^(3+)(aq.)+Na_(2)O_(2)("Solution")to`
B. `Fe^(3+)(aq.)+(NH_(4))_(2)S to `
C. `Mn^(2+)(aq.)+H_(2)O_(2)+NH_(3)("Solution")to`
D. `Fe^(2+)(aq.)+Na_(2)O_(2)("solution")to`

Answer

A

Explanation

`Cr^(3+)(aq.)+Na_(2)O_(2)sol. To CrO_(4)^(2-)(aq.)`
`Fe^(3+)(aq.)+(NH_(4))_(2)S to FeS darr` `Mn^(2+)(aq.)+H_(2)O_(2) +NH_(3) t MnO(OH)_(2)darr` or `MnO_(2)darr*2H_(2)O`
`Fe^(2+)(aq.)+Na_(2)O_(2) sol. To Fe(OH)_(2)darr`