Resistance of 0.2 M solution of an electrolyte is 50 Ω. The specific conductance of the solution is 1.4 S m−1. The resistance of 0.5 M solution of the same electrolyte is 280 Ω. The molar conductivity of 0.5 M solution of the electrolyte in S m2 mol−1 is

For 0.2 M solution, R=50Ωκ=14 S m−1=1.4×10−2 S cm−1The resistivity of the solution is related to specific conductance by ρ=1κ=11.4×10−2Ω cmIt is known that, R=ρ×la⇒Rρ=la⇒la=R×1ρ=50×1.4×10−2cm-1For 0.5 M solution, R=280 Ωκ=?la=50×1.4×10−2 cm-1The specific conductance of the solution is given by κ=1ρ=1R×laκ=1280×50×1.4×10−2=2.5×10−3 S cm−1Now, the molar conductivity of the solution is given by Λm=κ×1000M=2.5×10−3×10000.5=5.5 cm2 mol−1=5×10−4 S m2 mol−1Hence, the molar conductivity of 0.5 M solution of the electrolyte is 5×10−4 S m2 mol−1.