JEE Mains · Chemistry · STD 12 - 2. Electrochemistry
The pH and conductance of a weak acid (HX) was found to be 5 and \( 4 \times 10^{-5} \) S, respectively. The conductance was measured under standard condition using a cell where the electrode plates having a surface area of \( 1 \, cm^{2} \) were at a distance of 15 cm apart. The value of the limiting molar conductivity is ......... \( S \, m^{2} \, mol^{-1} \). (nearest integer) (Given: degree of dissociation of the weak acid (a) \(\ll 1\) )
- A 2
- B 4
- C 6
- D 8
Answer & Solution
Correct Answer
(C) 6
Step-by-step Solution
Detailed explanation
\(pH =5\) \(\left[ H ^{+}\right]=10^{-5}=[ HX ] \cdot \alpha\) \(=[ HX ] \cdot \frac{\Lambda_{ m }}{\Lambda_{ m }^{\infty}}\) \(\Lambda_{ m }=\frac{ k \times 1000}{[ HX ]}\) \(K = G . G ^*=4 \times 10^{-5} \times \frac{15}{1}=6 \times 10^{-4} S . cm ^{-1}\)…
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