1. Chemical Formula:

* Aluminum chloride has the chemical formula AlCl₃. This means each formula unit contains one aluminum ion (Al³⁺) and three chloride ions (Cl⁻).

2. Moles to Formula Units:

* One mole of any substance contains 6.022 x 10²³ formula units (Avogadro's number).

* Therefore, 3 moles of aluminum chloride contain 3 mol * 6.022 x 10²³ formula units/mol = 1.807 x 10²⁴ formula units.

3. Chloride Ions per Formula Unit:

* Each formula unit of AlCl₃ contains 3 chloride ions.

4. Total Chloride Ions:

* Multiply the number of formula units by the number of chloride ions per formula unit: (1.807 x 10²⁴ formula units) * (3 Cl⁻/formula unit) = 5.421 x 10²⁴ chloride ions.

Therefore, there are 5.421 x 10²⁴ chloride ions in 3 moles of aluminum chloride.