Question

The molar ionic conductivities of \[\ce{Al^3+}\] and \[\ce{SO^2-_4}\] are 189 S cm² mol⁻¹ and 160 S cm² mol⁻¹ respectively. The value of limiting molar conductivity of \[\ce{Al2(SO4)3}\] will be ______.

विकल्प

• 198 S cm² mol⁻¹

• 858 S cm² mol⁻¹

• 588 S cm² mol⁻¹

• 891 S cm² mol⁻¹

Answer 1

The molar ionic conductivities of \[\ce{Al^3+}\] and \[\ce{SO^2-_4}\] are 189 S cm² mol⁻¹ and 160 S cm² mol⁻¹ respectively. The value of limiting molar conductivity of \[\ce{Al2(SO4)3}\] will be 858 S cm² mol⁻¹.

Explanation:

Ionic molar conductivity or limiting molar conductivity \[\ce{Al^3+\lambda^\circ^3+_{Al}}\] = 189 S cm² mol⁻¹

Ionic molar conductivity or limiting molar conductivity `"SO"_4^(2-)(3λ_(SO_4^(2-))^0)` = 160 S cm² mol⁻¹

So, limiting molar conductivity of a \[\ce{Al2(SO4)3}\] compound \[\ce{Al2(SO4)3}\]

\[\ce{∧^\circ _{Al_2(SO_4)_3} = 2^\circ \lambda_{Al3+} + 3\lambda^\circ SO^2-_4^}\] 

= 2 (189) + 3 (160)

= 858 S cm² mol⁻¹