IIA (alkaline earth metals) and IIB (zinc family) resemble:

Options

A. `MgSO_(4)*7H_(2)O` is isomorphous with `ZnSO_(4)*7H_(2)O`
B. IIA and IIB cations are ont precipitated by `H_(2)S` in acidic medium
C. both (a) and (b)
D. None of the above

Answer

To solve the question regarding the resemblance between IIA (alkaline earth metals) and IIB (zinc family), we will analyze the statements provided and verify their accuracy step by step.

### Step 1: Analyze the First Statement
The first statement claims that MgSO4·7H2O is isomorphous with ZnSO4·7H2O.

1. **Definition of Isomorphous**: Isomorphous compounds are those that have the same crystal structure and similar chemical formulas.
2. **Chemical Formula Similarity**: Both compounds have the same formula type: MgSO4·7H2O and ZnSO4·7H2O. This satisfies the first condition for isomorphism.
3. **Atomic Size Similarity**: Magnesium (Mg) and Zinc (Zn) have similar ionic radii, which helps in forming similar crystal structures.
4. **X-ray Diffraction**: X-ray diffraction studies can confirm that both compounds exhibit similar crystal structures.

**Conclusion for Step 1**: The first statement is true.

### Step 2: Analyze the Second Statement
The second statement discusses the precipitation of cations from IIA and IIB groups by H2S in acidic medium.

1. **Cation Behavior in Acidic Medium**:
- IIA (alkaline earth metals) cations (like Mg²⁺, Ca²⁺) are not precipitated by H2S in acidic medium. This is because they do not form insoluble sulfides under these conditions.
- IIB (zinc family) cations (like Zn²⁺) can be precipitated by H2S in acidic medium, as they can form insoluble sulfides.

2. **Group Analysis**:
- Group IIA cations do not precipitate with H2S, while Group IIB cations do.

**Conclusion for Step 2**: The second statement is partially true; it correctly states that IIA cations do not precipitate with H2S, but incorrectly implies that IIB cations do not precipitate.

### Final Conclusion
Based on the analysis:
- The first statement is true.
- The second statement is partially true, as it misrepresents the behavior of IIB cations.

### Final Answer
The correct option is A (the first statement is true, and the second statement is partially true).

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