NEETChemistryElectrochemistry
The limiting molar conductivities of NH ₄ OH , NH ₄ Cl and NaOH are 271.6 , 149.7 and 248.1 S cm ^2 mol ⁻¹ respectively. What is the limiting molar conductivity of NaCl ?
Options
- A126.2 S cm ^2 mol ⁻¹
- B173.2 S cm ^2 mol ⁻¹
- C370.0 S cm ^2 mol ⁻¹
- D669.4 S cm ^2 mol ⁻¹
Correct answer
A. 126.2 S cm ^2 mol ⁻¹
Step-by-step solution
According to Kohlrausch's law of independent migration of ions: ^ _m( NH ₄ OH ) = ^ _m( NH ₄ Cl ) + ^ _m( NaOH ) - ^ _m( NaCl ) Rearranging the equation to solve for ^ _m( NaCl ) : ^ _m( NaCl ) = ^ _m( NH ₄ Cl ) + ^ _m( NaOH ) - ^ _m( NH ₄ OH ) Substituting the given values: ^ _m( NaCl ) = 149.7 + 248.1 - 271.6 ^ _m( NaCl ) = 397.8 - 271.6 = 126.2 S cm ^2 mol ⁻¹ Answer: 126.2 S cm ^2 mol ⁻¹