In salt analysis cations of group I and II precipitated in acidicmedium and therefore the solution remains acidic till group II. But from III group onwards cations precipitates in basic medium and hence filtrate of group II is to be boiled with con HNO_(3) before using it for III group. Which statements is not true for III group precipitate.

In salt analysis cations of group I and II precipitated in acidicmediu

1.	In salt analysis cations of group I and II precipitated in acidicmedium and therefore the solution remains acidic till group II. But from III group onwards cations precipitates in basic medium and hence filtrate of group II is to be boiled with con HNO_(3) before using it for III group. Which statements is not true for III group precipitate.
Answer» `(NH_(4))_(2)SO_(4)` cannot be usedin place `NH_(4)Cl` `NH_(4)NO_(3)` can be used in place of `NH_(4)Cl` `NH_(4)Cl` must be ADDED in excess before `NH_(4)OH` `NaOH` DISSOLVES only `Al(OH)_(3)` not `Cr(OH)_(3)` and `FE(OH)_(3)`. Solution :`NO_(3)^(-)`ion will OXIDIZE `Mn^(2+)` to `Mn^(3+)` and `Mn(OH)_(3)` will precipitate.