The density of KBr is 2.75 g `cm^(–3)`. The length of the edge of the unit cell is 654 pm. Show that KBr has face centered cubic structure. `(N = 6.023 x× 10^(23) mol^(–1)`, At. mass : K = 39, Br = 80)

Explanation

To show that KBr has a face-centered cubic (FCC) structure, we will use the given density, atomic masses, and the edge length of the unit cell.

### Step-by-Step Solution:

1. **Given Data**:
- Density of KBr (D) = 2.75 g/cm³
- Edge length of the unit cell (a) = 654 pm = \(654 \times 10^{-10}\) cm
- Atomic mass of K (m_K) = 39 g/mol
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