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 molarity of the above solution?

Options

• 0.204 M

• 0.024 M

• 0.420 M

• 4.021 M

Answer 1

0.024 M

Explanation:

Given: Mass of BaCl₂ = 2 g

Volume of solution = 400 cm³ = 0.400 L

Atomic masses: Ba = 137, Cl = 35.5

Specific conductivity is not required for molarity calculation.

Molar mass of BaCl₂ = 137 + (2 × 35.5)

= 137 + 71

= 208 g/mol

Moles of BaCl₂ = `2/208`

= 0.009615 mol

Molarity = `"Moles"/"Volume in L"`

= `0.009615/0.400`

= 0.024 mol/L