Calcium chloride when dissolved in water dissociates into its ions according to the following equation.

CaCl(aq) → Ca2+ (aq) + 2Cl^– (aq)

Calculate the number of ions obtained from CaCl2 when 222 g of it is dissolved in water.

Molar mass of CaCl₂ = The atomic mass of Ca + 2 × the atomic mass of Cl

= 40 + 35.5 × 2 = 111 g/mol

1 mole of calcium chloride = 111g

Thus, 222g of CaCl₂ is equivalent to 2 moles of CaCl₂

Since 1 formula unit CaCl₂ gives 3 ions (one Ca²⁺ cation and two Cl^- anions),

Therefore, 1 mole of CaCl₂ will give 3 moles of ions

2 moles of CaCl₂ would give 3 × 2 = 6 moles of ions.

No. of ions = No. of moles of ions × Avogadro number

= 6 × 6.022 ×10²³

= 36.132 ×10²³

= 3.6132 ×10²⁴ ions