The density of KBr is ` 2.75 g//cm^(3)` . The length of the unit cell is 654 pm. Atomic mass of K= 39, Br =80. Then what is true about the predicted nature of the solid ?

Options

A. It has ` 4 K^(+) and 4 Br^(-)` ions per unit cell
B. It is face -centred
C. It has rock- salt type structure
D. It can have schottky defects

Explanation

To determine the predicted nature of the solid KBr based on the given data, we will follow these steps:

### Step 1: Gather the given data
- Density (D) of KBr = 2.75 g/cm³
- Length of the unit cell (a) = 654 pm = 654 x 10^(-10) cm (since 1 pm = 10^(-12) m and 1 cm = 10^(-2) m)
- Atomic mass of K (Potassium) = 39 g/mol
- Atomic mass of Br (Bromine) = 80 g/mol

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