A salt `MX` has `NaCl` type lattice in which `r` is the minimum distance between `M^(z+)` and `X^(z-)`. Each `M^(z+)` ion is surrounded by

Options

A. `6X^(z-)`ions each at a distance `r`
B. `12M^(z+)` ions, each at a distance `sqrt(2)r`
C. `8oX^(z-)` ions, each at a distance `sqrt(3)r`.
D. `12M^(z+)` ions, each at a distance `sqrt(4)r`.

Explanation

To solve the question regarding the salt `MX` with a NaCl type lattice, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure Type**:
The question states that the salt `MX` has a NaCl type lattice. This indicates that it has a face-centered cubic (FCC) structure, similar to that of sodium chloride (NaCl).

**Hint**: Recall the characteristics of the NaCl structure, which is a face-centered cubic lattice.

2. **Understand Ion Arrangement**:
In a NaCl structure, each sodium ion (Na⁺) is surrounded by six chloride ions (Cl⁻) in an octahedral arrangement. This means that each ion type has a coordination number of 6.

**Hint**: Visualize the arrangement of ions in the FCC lattice to understand how many ions surround each ion.

3. **Apply to the Given Salt `MX`**:
Since `MX` has the same type of lattice as NaCl, we can conclude that each `M^(z+)` ion will also be surrounded by six `X^(z-)` ions, just as each Na⁺ is surrounded by six Cl⁻ ions in NaCl.

**Hint**: Consider the symmetry and arrangement in the FCC structure to determine the coordination number.

4. **Conclusion**:
Therefore, each `M^(z+)` ion in the salt `MX` is surrounded by 6 `X^(z-)` ions.

**Final Answer**: Each `M^(z+)` ion is surrounded by **6 `X^(z-)` ions**.

### Summary of the Solution:
- The salt `MX` has a NaCl type lattice (FCC).
- Each `M^(z+)` ion is surrounded by 6 `X^(z-)` ions.
- Thus, the answer is **6 `X^(z-)` ions**.