For crystal sodium chloride, state
(i) the type of lattice in which it crystallises.
(ii) co-ordination number of each sodium ion and chloride ion in the crystal lattice.
(iii) number of sodium and chloride ions present in a unit cell of sodium chloride.
(iv) the structural arrangement of sodium chloride crystals.

Explanation

To solve the question regarding the crystal structure of sodium chloride (NaCl), we will address each part step by step.

### Step-by-Step Solution:

**(i) Type of Lattice in Which Sodium Chloride Crystallizes:**
Sodium chloride crystallizes in a face-centered cubic (FCC) lattice structure. In this structure, the chloride ions (Cl⁻) form a cubic close-packed (CCP) arrangement.

**(ii) Coordination Number of Each Sodium Ion and Chloride Ion:**
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