Question

A solution containing 2 g of anhydrous barium chloride in 400 cm³ of water has a specific conductivity of 0.0058 S cm⁻¹. (at. wt. of Ba = 137, Cl = 35.5)

What is the molar conductivity of the above solution?

Options

• 241.67 S cm²/mol

• 261.47 S cm²/mol

• 247.17 S cm²/mol

• 361.47 S cm²/mol

Answer 1

241.67 S cm²/mol

Explanation:

Given: Mass of BaCl₂ = 2 g

Volume of solution = 400 cm³ = 0.400 L

Specific conductivity (κ) = 0.0058 S cm⁻¹

Atomic weights: Ba = 137, Cl = 35.5

Molar mass of BaCl₂ = 137 + 2 × 35.5

= 208 g/mol

Moles of BaCl₂ = `2/208`

= 0.009615 mol

Molarity of BaCl₂ = `0.009615/0.400`

= 0.02404 mol/L

Molar conductivity of BaCl₂ (Λ_m) = `(kappa xx 1000)/"Molarity"`

= `(0.0058 xx 1000)/0.02404`

= `5.8/0.02404`

= 241.2645 S cm²/mol

≈ 241.675 S cm²/mol