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प्रश्न
Assertion: Λm for weak electrolytes shows a sharp increase when the electrolytic solution is diluted.
Reason: For weak electrolytes degree of dissociation increases with dilution of solution.
विकल्प
Both assertion and reason are true and the reason is the correct explanation of assertion.
Both assertion and reason are true and the reason is not the correct explanation of assertion.
Assertion is true but the reason is false.
Both assertion and reason are false.
Assertion is false but reason is true.
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उत्तर
Both assertion and reason are true and the reason is the correct explanation of assertion.
Explanation:
Weak electrolytes dissociate partially in concentrated solution. On dilution, their degree of dissociation increases hence their Am increases sharply.
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संबंधित प्रश्न
The conductivity of 0.20 M solution of KCl at 298 K is 0.025 S cm−1. Calculate its molar conductivity.
State Kohlrausch Law.
Why conductivity of an electrolyte solution decreases with the decrease in concentration ?
The conductivity of sodium chloride at 298 K has been determined at different concentrations and the results are given below:
| Concentration/M | 0.001 | 0.010 | 0.020 | 0.050 | 0.100 |
| 102 × κ/S m−1 | 1.237 | 11.85 | 23.15 | 55.53 | 106.74 |
Calculate ∧m for all concentrations and draw a plot between ∧m and c1/2. Find the value of `∧_m^0`.
The conductivity of 0.02M AgNO3 at 25°C is 2.428 x 10-3 Ω-1 cm-1. What is its molar
conductivity?
A steady current of 2 amperes was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO4and ZnSO4 until 2.8g of Fe deposited at the cathode of cell X. How long did the current flow? Calculate the mass of Zn deposited at the cathode of cell Y.
(Molar mass: Fe=56g mol-1,Zn=65.3g mol-1,1F=96500C mol-1)
Conductivity always decreases with decrease in concentration both, for weak and strong electrolytes because of the fact that ____________.
Kohlrausch law of independent migration of ions states ____________.
Which of the statements about solutions of electrolytes is not correct?
When acidulated water (dil.H2SO4 solution) is electrolysed, will the pH of the solution be affected? Justify your answer.
Why on dilution the m Λm of \[\ce{CH3COOH}\] increases very fast, while that of \[\ce{CH3COONa}\] increases gradually?
Consider figure and answer the question to given below.
How will the concentration of Zn2+ ions and Ag+ ions be affected after the cell becomes ‘dead’?
An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to :-
Which of the following halogen acids is the strongest reducing agent?
Which of the following increases with the increase in the concentration of the solution?
The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol−1. What is the dissociation constant of acetic acid? Choose the correct option.
\[\begin{array}{cc}
\end{array}\]\[\begin{bmatrix}
\ce{\Lambda^{\circ}_{H^+} = 350 S cm^2 mol^{-1}}\\
\ce{\Lambda^{\circ}_{CH_3COO^-} = 50 S cm^2 mol^{-1}}
\end{bmatrix}\]
The following questions are case-based questions. Read the passage carefully and answer the questions that follow:
| Rahul set up an experiment to find the resistance of aqueous KCl solution for different concentrations at 298 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 the null point, he also calculated the conductivity K and molar conductivity ∧m and recorded his readings in tabular form. |
| S. No. | Conc. (M) |
k S cm−1 | ∧m S cm2 mol−1 |
| 1. | 1.00 | 111.3 × 10−3 | 111.3 |
| 2. | 0.10 | 12.9 × 10−3 | 129.0 |
| 3. | 0.01 | 1.41 × 10−3 | 141.0 |
Answer the following questions:
(a) Why does conductivity decrease with dilution? (1)
(b) If `∧_"m"^0` of KCl is 150.0 S cm2 mol−1, calculate the degree of dissociation of 0.01 M KCI. (1)
(c) If Rahul had used HCl instead of KCl then would you expect the ∧m values to be more or less than those per KCl for a given concentration? Justify. (2)
OR
(c) Amit a classmate of Rahul repeated the same experiment with CH3COOH solution instead of KCl solution. Give one point that would be similar and one that would be different in his observations as compared to Rahul. (2)
The specific conductance of 2.5 × 10-4 M formic acid is 5.25 × 10-5 ohm-1 cm-1. Calculate its molar conductivity and degree of dissociation.
Given `λ°_("H"^+)` = 349.5 ohm-1 cm2 mol-1 and
`λ°_("HCOO"^-) = 50.5 " ohm"^-1 "cm"^2 "mol"^-1`
