During the crystallisation one fourth mole of `Cu_(2) CI_(2)` in molten state one millimole of zinc chloride is added. How many cuprous ions are removed? Calculate the number of lattice vacancies created in the crystal.

Explanation

To solve the problem, we need to determine how many cuprous ions (Cu^+) are removed when 1/4 mole of cuprous chloride (Cu2Cl2) is crystallized with the addition of 1 millimole of zinc chloride (ZnCl2). We also need to calculate the number of lattice vacancies created in the crystal.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- When zinc chloride (ZnCl2) is added to cuprous chloride (Cu2Cl2), it can lead to the formation of copper(II) ions (Cu^2+) and the removal of cuprous ions (Cu^+).
- The reaction can be represented as:
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