salt analysis

Question

Ammonium hydroxide is added group-wise in qualitative analysis to:

RankGuru · Accepted Answer

In **Qualitative Inorganic Analysis**, cations are separated into groups based on their solubility products ($K_{sp}$).
- **Group III Cations** ($Fe^{3+}, Al^{3+}, Cr^{3+}$) have relatively low solubility products for their hydroxides.
- **Group Reagent**: $NH_4OH$ in the presence of $NH_4Cl$.
- **Function of $NH_4Cl$**: It suppresses the ionization of $NH_4OH$ (Common Ion Effect), ensuring that the concentration of $OH^-$ ions is just enough to precipitate Group III hydroxides but not high enough to precipitate Group IV or later cations (like $Mg^{2+}$).

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salt analysis

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