Question

If a salt solution containing `Fe^(2+)` is not treated with a few drops of `HNO_(3)` before starting for group III the ppt. obtained in group III will be
A. redish brown in colour
B. dirty green in colour
C. black
D. white

Answer 1

If `Fe^(2+)` ions are not oxidised to `Fe^(3+)` ions before proceeding for group III, dirty green ppt. of `Fe(OH)_(2)` will be obtained.
`Fe^(2+) +2NH_(4)OH to underset("Dirty green")(Fe(OH)_2)+NH_(4)^(+)`