‹ Back to the paper
Vishal set up an experiment to find the resistance of aqueous solution for different concentrations…
Vishal set up an experiment to find the resistance of aqueous $\text{KCl}$ solution for different concentrations at $298\text{ K}$ using a conductivity cell connected to a Wheatstone bridge. He fed the Wheatstone bridge with A.C. power in the audio frequency range 550 to 5000 cycles per second. Once the resistance was calculated from null point, he also calculated the conductivity ($\kappa$) and molar conductivity ($\Lambda_m$) and recorded his readings in tabular form which is given below.
| S.No. | Conc. (M) | $\kappa\text{ (S cm}^{-1}\text{)}$ | $\Lambda_m\text{ (S cm}^2\text{ mol}^{-1}\text{)}$ |
|---|---|---|---|
| 1. | $1\cdot00$ | $111\cdot3 \times 10^{-3}$ | $111\cdot3$ |
| 2. | $0\cdot10$ | $12\cdot9 \times 10^{-3}$ | $129\cdot0$ |
| 3. | $0\cdot01$ | $1\cdot41 \times 10^{-3}$ | $141\cdot0$ |
Read the passage carefully and answer the questions that follow.
(i)[1.0]
Why did the molar conductivity increase though the conductivity decreased with dilution?
(ii)[1.0]
If molar conductivity at infinite dilution ($\Lambda_m^\circ$) of $\text{KCl}$ is $150\cdot0\text{ S cm}^2\text{ mol}^{-1}$, calculate the degree of dissociation of $0\cdot01\text{ M KCl}$.
(iii)[1.0]
The conductivity of a $0\cdot01\text{ M}$ solution of acetic acid at $298\text{ K}$ is $1\cdot65 \times 10^{-4}\text{ S cm}^{-1}$. Calculate the molar conductivity of the solution.
Answer
No answer yet.
From ISC 2026 Specimen Chemistry Paper 1, question 1(C).