Question

The solubility of Co₂[Fe(CN)₆] in water at 25°C from the following data:

Conductivity of saturated solution of Co₂[Fe(CN)₆] = 2.06 × 10⁻⁶ ohm⁻¹ cm⁻¹ and that of water = 4.1 × 10⁻⁷ ohm⁻¹ cm⁻¹. The ionic molar conductivities of Co²⁺ and [Fe(CN)₆]⁴⁻ are 86 and 444 ohm⁻¹ cm² mol⁻¹ respectively, is ______ × 10⁻⁶ mol/L.

Options

• 2.67

• 3.98

• 4.45

• 5.34

Answer 1

The solubility of Co₂[Fe(CN)₆] in water at 25°C from the following data:

Conductivity of saturated solution of Co₂[Fe(CN)₆] = 2.06 × 10⁻⁶ ohm⁻¹ cm⁻¹ and that of water = 4.1 × 10⁻⁷ ohm⁻¹ cm⁻¹. The ionic molar conductivities of Co²⁺ and [Fe(CN)₆]⁴⁻ are 86 and 444 ohm⁻¹ cm² mol⁻¹ respectively, is 2.67 × 10⁻⁶ mol/L.

Explanation:

Conductivity of ion Co²⁺ and [Fe(CN)₆]^4–

= 2.06 × 10^–6 – 4.1 × 10^–7 ohm^–1 cm^–1

= 1.65 × 10^–6 ohm^–1 cm^–1

∴ S = `(1.65 xx 10^6)/(616)`

= 2.67 × 10^–9 mol/cm³

= 2.67 × 10^–6 mol/L