With the help of a graph explain why it is not possible to determine λ m ∞ for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte.

It is not possible to determine λ m ∞ (limiting molar conductivity) for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte. Because weak electrolyte dissociated to a much lesser extent as compared to a strong electrolyte. There is a large increase in conductance with dilution near the infinite dilution, it is due the concentration of the weak electrolyte is reduced.

With the help of a graph explain why it is not possible to determine λ m ∞ for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte.

It is not possible to determine λ m ∞ (limiting molar conductivity) for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte. Because weak electrolyte dissociated to a much lesser extent as compared to a strong electrolyte. There is a large increase in conductance with dilution near the infinite dilution, it is due the concentration of the weak electrolyte is reduced.

The conductivity of 0 . 10 M solution of KCl at 298 K is 0 . 0129 S cm - 1 . Calculate its molar conductivity.

Given: The concentration of the solution = 0 . 10 M The conductivity of the solution k = 0 . 0129 S cm - 1 = 1 . 29 × 10 - 2 ohm - 1 cm - 1 Molar conductivity, ∧ m = k × 1000 M ohm - 1 cm 2 mol - 1 = 1 . 29 × 10 - 2 × 1000 0 . 10 ohm - 1 cm 2 mol - 1 = 129 ohm - 1 cm 2 mol - 1

The molar conductivity of 0 . 05 M BaCl 2 solution at 25 ° C is 223 Ω - 1 cm 2 mol - 1 . What is its conductivity?

Given, Concentration ( C ) = 0 . 05 M Molar conductivity ( λ m ) = 223 Ω - 1 cm 2 mol - 1 As we know, Molar conductivity, λ m = 1000 × k C ⋯ ⋯ ⋯ ⋯ ( i ) ∴ k = λ m × C 1000 ⋯ ⋯ ⋯ ⋯ ⋯ ( ii ) Put all the values in equation ii , = 223 × 0 . 05 1000 = 0 . 01115 S cm - 1 or Ω - 1 cm - 1 Therefore, the molar conductivity of BaCl 2 solution is 0 . 01115 S cm - 1 or Ω - 1 cm - 1 .

Match List - I with List - II : List - I (Parameter) List - II (Unit) (a) Cell constant (i) S cm 2 mol - 1 (b) Molar conductivity (ii) Dimensionless (c) Conductivity (iii) m - 1 (d) Degree of dissociation of electrolyte (iv) Ω - 1 m - 1

(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)

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With the help of a graph explain why it is not possible to determine $λ_{m}^{\infty}$ for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte.

Important Questions on Electrochemistry

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The molar conductivities of

HCl, NaCl, {CH}_{3} COOH

and

{CH}_{3} COONa

at infinite dilution follow the order

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

291 K

, saturated solution of

{BaSO}_{4}

was found to have a specific conductivity of

3.648 \times 10^{- 6} {ohm}^{- 1} {cm}^{- 1}

and that of water being used is

1.25 \times 10^{- 6} {ohm}^{- 1} {cm}^{- 1}

. If the ionic conductance's of

{Ba}^{2 +}

and

{SO}_{4}^{2 -}

are

110

and

136.6 {ohm}^{- 1} {cm}^{2} {mol}^{- 1}

respectively, the solubility of

{BaSO}_{4}

291 K

will be [Atomic masses of

Ba - 137, S - 32, 0 - 16]

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

In the plot of molar conductivity $(\land_{m})$ vs square root of concentration $(c^{1 / 2})$ , following curves are obtained for two electrolytes A and B :

Question Image

Answer the following :
Predict the nature of electrolytes A and B.

EASY

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Define the equivalent conductivity.

EASY

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The pair of electrolytes that possess same value for the constant

(A)

in the Debye - Huckel - Onsagar equation,

λ_{m} = λ_{m} ° - A \sqrt{C}

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The specific conductivity of a solution containing

5

g of anhydrous

{BaCl}_{2}

( molecular weight

= 208

) in

1000 {cm}^{3}

of a solution is found to be

0.0058 {ohm}^{- 1} {cm}^{- 1}

. Calculate the molar and equivalent conductivity of the solution.

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The resistance of conductivity cell with cell constant

1.14 {cm}^{- 1}

, containing

0.001 M KCl

298 K

1500 Ω

. The molar conductivity of

0.001 M KCl

solution at

298 K

S {cm}^{2} {mol}^{- 1}

is (Integer answer)

EASY

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The conductivity of

0.10 M

solution of

KCl

298 K

0.0129 S {cm}^{- 1}

. Calculate its molar conductivity.

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The graph of

\sqrt{C} vs \land_{m}

for an aqueous solution of which substance is not obtained as a straight line?

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Given below are two statements:
Statement I : The limiting molar conductivity of $KCl$ (strong electrolyte) is higher compared to that of $\mathrm{CH}_{3} \mathrm{COOH}$ (weak electrolyte).
Statement II : Molar conductivity decreases with decrease in concentration of electrolyte.

In the light of the above statements, choose the most appropriate answer from the options given below:

EASY

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

State Kohlrausch law of independent migration of ions. Write an expression for the molar conductivity of acetic acid at infinite dilution according to Kohlrausch. law.

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Give a reason for the following.
Conductivity of dilute hydrochloric acid is greater than that of acetic acid.

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Define molar conductivity of a solution. Explain how molar conductivity changes with change in concentration of solution for a weak and a strong electrolyte.

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The molar conductivity of a

0.5 mol {dm}^{- 3}

solution of

A g N O_{3}

with electrolytic conductivity of

5.76 \times 10^{- 3} S c m^{- 1}

298 K

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

The molar conductivity of

0.05 M {BaCl}_{2}

solution at

25 ° C

223 Ω^{- 1} {cm}^{2} {mol}^{- 1}

. What is its conductivity?

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Define the following and write the formula and unit :

Equivalent conductivity

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Distinguish between electronic conduction and electrolytic conduction.

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Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Match List - I with List - II :

	List - I (Parameter)		List - II (Unit)
(a)	Cell constant	(i)	$S {cm}^{2} {mol}^{- 1}$
(b)	Molar conductivity	(ii)	Dimensionless
(c)	Conductivity	(iii)	$m^{- 1}$
(d)	Degree of dissociation of electrolyte	(iv)	$Ω^{- 1} m^{- 1}$

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Which one of the following graphs between molar conductivity

(Λ_{m})

versus

\sqrt{C}

is correct?

HARD

Chemistry>Physical Chemistry>Electrochemistry>Conductance in Electrolytic Solutions

Resistance of 0.2 M solution of an electrolyte is

50 Ω

. The specific conductance of the solution is

{1.4 S m}^{-1}

. The resistance of 0.5 M solution of the same electrolyte is

280 Ω

. The molar conductivity of 0.5 M solution of the electrolyte in

{S m}^{2} {mol}^{-1}

is :

With the help of a graph explain why it is not possible to determine λm∞ for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte.

Important Questions on Electrochemistry

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With the help of a graph explain why it is not possible to determine $λ_{m}^{\infty}$ for a weak electrolyte by extrapolating the concentration-molar conductance curve as for strong electrolyte.