Question: 48. Match List-I With List-II.
| List-I (Ion) | List-II (Group Number in Cation Analysis) |
|---|---|
| A. Co2+ | I. Group-I |
| B. Mg2+ | II. Group-III |
| C. Pb2+ | III. Group-IV |
| D. Al3+ | IV. Group-VI |
Choose the correct answer from the options given below:
(1) A-III, B-IV, C-II, D-I
(2) A-III, B-IV, C-I, D-II
(3) A-III, B-II, C-IV, D-I
(4) A-III, B-II, C-I, D-IV
Answer: Option (2)
Explanation:
(based on qualitative inorganic analysis – Group separation):
In classical salt analysis, cations are grouped according to the reagent that precipitates them.
Group-wise classification of given ions
A. Ca²⁺ → Group III
Group III cations are precipitated as hydroxides by NH₄OH in presence of NH₄Cl.
Calcium belongs to Group III (alkaline earth metals) in qualitative analysis.
B. Mg²⁺ → Group IV
Magnesium ions are not precipitated in Group III.
They are precipitated in Group IV as MgNH₄PO₄ using Na₂HPO₄ in presence of NH₄OH and NH₄Cl.
C. Pb²⁺ → Group I
Group I cations form insoluble chlorides with dilute HCl.
Lead(II) chloride (PbCl₂) is sparingly soluble and hence Pb²⁺ belongs to Group I.
D. Al³⁺ → Group III
Aluminium forms Al(OH)₃, precipitated by NH₄OH in presence of NH₄Cl.
Hence it belongs to Group III.