Most Important Selected Qs for JEE AdvancedChemistryElectrochemistry
Consider the following information array |c|c| Electrolyte & array l Molar conductivity at infinite dilution at 25^ C in S cm ^2 ~mol ⁻¹ array HCl & 426 NaCl & 126 NaC ₄ H ₅ O ₂ & 83 array If conductivity of 0.001 M H ₆ C ₄ O ₂ solution is 3.83 10⁻⁵ ~S ~cm ⁻¹ and neglect the variation of conductivity with concentration. The correct statement(s) about H ₆ C ₄ O ₂ assuming it to be a weak acid is/are
Options
- AThe degree of dissociation of acid H ₆ C ₄ O ₂ is 10 %
- BThe degree of dissociation of acid H ₆ C ₄ O ₂ is 26 %
- CThe dissociation constant of acid H ₆ C ₄ O ₂ is 1.11 10⁻⁵ M
- DThe dissociation constant of acid H ₆ C ₄ O ₂ is 1.11 10⁻⁷ M
Correct answer
C. The dissociation constant of acid H ₆ C ₄ O ₂ is 1.11 10⁻⁵ M
Step-by-step solution
The Molar conductivity of the dissociated form of H ₆ C ₄ O ₂ is aligned & _m^ ( H ⁺, H ₅ C ₄ O ₂⁻ )= _ m ^ ( HCl )+ _ m ^ NaH ₅ C ₄ O ₂- _ m ^ ( NaCl ) & =426+83-126=383 ~S ~cm ^2 ~mol ⁻¹ aligned The molar conductivity of H ₆ C ₄ O ₂= aligned & 3.83 10⁻⁵ 1000 0.001 & =38.3 ~S ~cm ^2 ~mol ⁻¹ & = 38.3 383 =0.1 & ~K _ a = C ^2 1- =1.11 10⁻⁵ aligned