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प्रश्न
Define “Molar conductivity”.
Define molar conductivity for the solution of an electrolyte.
Define molar conductivity of an electrolytic solution.
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उत्तर १
Molar conductivity is the conductance of a volume of solution containing 1 mole of dissolved electrolyte when placed between two parallel electrodes 1 cm apart and large enough to contain between them all the solution.
उत्तर २
The conductivity, which is shown by all the ions when 1 mol of electrolyte is dissolved in the solution, is called molar conductivity; it is expressed by ∧m (lambda). If 1 mol of electrolyte is present in Vm cm3 of electrolyte solution, then ∧m = κ × V
= `(kappa xx 1000)/"Molarity" = (kappa xx 1000)/M`
Its unit is ohm−1 cm2 mol−1 or S cm2 mol−1.
Notes
Students should refer to the answer according to their questions
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संबंधित प्रश्न
Resistance of conductivity cell filled with 0.1 M KCl solution is 100 ohms. If the resistance of the same cell when filled with 0.02 M KCl solution is 520 ohms, calculate the conductivity and molar conductivity of 0.02 M KCl solution. [Given: Conductivity of 0.1 M KCl solution is 1.29 S m-1 .]
State Kohlrausch’s law of independent migration of ions.
The molar conductivity of cation and anion of salt BA are 180 and 220 mhos respectively. The molar conductivity of salt BA at infinite dilution is_____________ .
(a) 90 mhos.cm2
(b) 110 mhos.cm2.mol-1
(c) 200 mhos.cm2.mol-1
(d) 400 mhos.cm2.mol-1
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.
Define limiting molar conductivity.
The conductivity of 0.20 mol L−1 solution of KCl is 2.48 × 10−2 S cm−1. Calculate its molar conductivity and degree of dissociation (α). Given λ0 (K+) = 73.5 S cm2 mol−1 and λ0 (C1−) = 76.5 S cm2 mol−1.
Why does the conductivity of a solution decrease with dilution?
The molar conductivity of 0.025 mol L−1 methanoic acid is 46.1 S cm2 mol−1. Calculate its degree of dissociation and dissociation constant. Given \[\ce{λ^0_{(H^+)}}\] = 349.6 S cm2 mol−1 and \[\ce{λ^0_{(HCOO^-)}}\] = 54.6 S cm2 mol−1.
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`.
10.0 grams of caustic soda when dissolved in 250 cm3 of water, the resultant gram molarity of solution is _______.
(A) 0.25 M
(B) 0.5 M
(C) 1.0 M
(D) 0.1 M
The conductivity of 0.02 M AgNO3 at 25°C is 2.428 × 10−3 Ω−1 cm−1. What is its molar conductivity?
Write mathematical expression of molar conductivity of the given solution at infinite dilution.
Calculate the degree of dissociation (α) of acetic acid if its molar conductivity (Λm) is 39.05 S cm2 mol−1.
(Given \[\ce{\lambda^{\circ}_{(H^+)}}\] = 349.6 S cm2 mol−1 and \[\ce{\lambda^{\circ}_{(CH_3COO^-)}}\] = 40.95 S cm2 mol−1)
How can you determine limiting molar conductivity, 0 m for strong electrolyte and weak electrolyte?
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)
Molar conductivity denoted by the symbol Λm is related to the conductivity of the solution by the equation (k is the conductivity and c is the concentration).
Kohlrausch law of independent migration of ions states ____________.
Which of the statements about solutions of electrolytes is not correct?
\[\ce{\Lambda^0_m(NH4OH)}\] is equal to ______.
Solutions of two electrolytes ‘A’ and ‘B’ are diluted. The Λm of ‘B’ increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Justify your answer.
When acidulated water (dil.H2SO4 solution) is electrolysed, will the pH of the solution be affected? Justify your answer.
Write the cell reaction of a lead storage battery when it is discharged. How does the density of the electrolyte change when the battery is discharged?
Why on dilution the m Λm of \[\ce{CH3COOH}\] increases very fast, while that of \[\ce{CH3COONa}\] increases gradually?
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.
Assertion: Copper sulphate can be stored in zinc vessel.
Reason: Zinc is less reactive than copper.
The limiting molar conductivities Λ° for NaCl, KBr and KCl are 126, 152 and 150 S cm2 mol–1 respectively. The limiting molar conductivity Λ° for NaBr is ______.
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 molar conductance of NaCl, HCl, and CH3COONa at infinite dilution are 126.45, 426.16, and 91.0 S cm2 mol−1 respectively. The molar conductance of CH3COOH at infinite dilution is. Choose the right option for your answer.
The solubility of Co2[Fe(CN)6] in water at 25°C from the following data:
Conductivity of saturated solution of Co2[Fe(CN)6] = 2.06 × 10−6 ohm−1 cm−1 and that of water = 4.1 × 10−7 ohm−1 cm−1. The ionic molar conductivities of Co2+ and [Fe(CN)6]4− are 86 and 444 ohm−1 cm2 mol−1 respectively, is ______ × 10−6 mol/L.
The variation of molar conductivity with concentration of an electrolyte (X) m aqueous solution is shown in the given figure.
The electrolyte X is ______.
Conductivity of 2 × 10−3 M methanoic acid is 8 × 10−5 S cm−1. Calculate its molar conductivity and degree of dissociation if `∧_"m"^0` for methanoic acid, is 404 S cm2 mol−3.
Assertion (A): Molar conductivity decreases with increase in concentration.
Reason (R): When concentration approaches zero, the molar conductivity is known as limiting molar conductivity.
Which of the following solutions will have the highest conductivity at 298 K?
The resistance of a conductivity cell with a 0.1 M KCl solution is 200 ohm. When the same cell is filled with a 0.02 M NaCl solution, the resistance is 1100 ohm. If the conductivity of 0.1 M KCl solution is 0.0129 ohm-1 cm-1, calculate the cell constant and molar conductivity of 0.02 M NaCl solution.
The solution of two electrolytes A and B are diluted. ^m of B increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Give a reason.
