Q.

0.2% (w/v) solution of NaOH is measured to have resistivity 870.0 mΩ m. The molar conductivity of the solution will be ______ ×102 mS dm2 mol-1. (Nearest integer)   [2025]


Ans.

(23)

Molarity of NaOH (C)=(%w/v)×10MNaOH

=0.2×1040=0.05M

ρ=870 m=870×10-3Ω×100 cm=87 Ω cm

κ=1ρ=187S cm-1

Λm=1000κCS cm2mol-1

=100087×0.05S cm2mol-1=229.885S cm2mol-1

=229.885×1000mS (10-1dm)2mol-1

=22.99×102mS dm2mol-1