The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol–1. The dissociation constant of acetic acid is :

(\(\mathrm{\Lambda_{H^{+}}^{o} \ = \ 350 \ S \ cm^{2} \ mol^{-1} }\))
(\(\mathrm{\mathrm{\Lambda_{CH_{3}COO^{-}}^{o} \ = \ 50 \ S \ cm^{2} \ mol^{-1} }}\))

1. 1.75×10-5 mol L–1 

2. 2.50×10-5 mol L–1 

3. 1.75×10-4 mol L–1 

4. 2.50×10-4 mol L–1 

Subtopic:   Kohlrausch Law & Cell Constant |
 60%
Level 2: 60%+
NEET - 2021
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The molar conductance of NaCl, HCI, and CH3COONa at infinite dilution are 126.45, 426.16, and 91.0 S cm mol–1 respectively. The molar conductance of CH3COOH at infinite dilution will be:

1. 698.28 S cm2 mol–1 2. 540.48 S cm2 mol–1
3. 201.28 S cm2 mol–1 4. 390.71 S cm2 mol–1
Subtopic:   Kohlrausch Law & Cell Constant |
 84%
Level 1: 80%+
NEET - 2021
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In a typical fuel cell, the reactants (R) and products (P) are: 

1. R = H2(g), O2(g); P = H2O2(l)
2. R = H2(g), O2(g); P = H2O(l)
3. R = H2(g), O2(g), C l2(g); P = HClO4(aq)
4. R = H2(g), N2(g); P = NH3(aq)

Subtopic:  Batteries & Salt Bridge |
 75%
Level 2: 60%+
NEET - 2020
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Given below are half-cell reactions:
\(\text{MnO}_{4}^{-}+8 \text{H}^{+}+5 \text{e}^{-} \rightarrow \text{Mn}^{2+}+4 \text{H}_{2} \text{O}, \)
\( \text{E}_{\text{Mn}^{2+}}^{\circ} / \text{MnO}_{4}^{-}=-1.510 \text{ V} \)
\( \frac{1}{2} \text{O}_{2}+2 \text{H}^{+}+2 \text{e}^{-} \rightarrow \text{H}_{2} \text{O}, \)
\( \text{E}_{\text{O}_{2} / \text{H}_{2} \text{O}}^{\circ}=+1.223 \text{ V}\)
Will the permanganate ion, \(\text{MnO}_{4}^{-}\) , liberate \(\text{O}_{2}\) from water in the presence of an acid?

1. No, because \(\text{E}_{\text {cell }}^{\circ}=-2.733 \text{ V}\)
2. Yes, because \(\text{E}_{\text {cell }}^{\circ}=+0.287 \text{ V}\)
3. No, because \(\text{E}_{\text {cell }}^{\circ}=-0.287 \text{ V}\)
4. Yes, because \(\text{E}_{\text {cell }}^{\circ}=+2.733 \text{ V}\)
Subtopic:  Electrode & Electrode Potential |
Level 3: 35%-60%
NEET - 2022
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Find the emf of the cell in which the following reaction takes place at 298 K:
\(\mathrm{Ni}(\mathrm{s})+2 \mathrm{Ag}^{+}(0.001 \mathrm{M}) \rightarrow \mathrm{Ni}^{2+}(0.001 \mathrm{M})+2 \mathrm{Ag}(\mathrm{s}) \)

\(\small{\text { (Given that } \mathrm{E}_{\text {cell }}^{\circ}=1.05 \mathrm{~V}; \dfrac{2.303 \mathrm{RT}}{\mathrm{F}}=0.059} )\)

1. 1.05 V 2. 1.0385 V
3. 1.385 V 4. 0.9615 V
Subtopic:  Nernst Equation |
Level 3: 35%-60%
NEET - 2022
Hints

The three cells with their \(E^\circ_{\text{(cell)}}\) values are given below:

Cells \(E^\circ_{\text{(cell)}}/V\)
(a) Fe|Fe2+||Fe3+|Fe 0.404
(b) Fe|Fe2+||Fe3+, Fe2+|Pt 1.211
(c) Fe|Fe3+||Fe3+, Fe2+|Pt 0.807
The standard Gibbs free energy change values for three cells are, respectively:
(F represents the charge on 1 mole of electrons.)
 
1. –1.212 F, –1.211 F, –0.807 F
2. +2.424 F, +2.422 F, +2.421 F
3. –0.808 F, –2.422 F, –2.421 F
4. –2.424 F, –2.422 F, –2.421 F
Subtopic:  Faraday’s Law of Electrolysis |
 59%
Level 3: 35%-60%
NEET - 2022
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\(\land^o_m\) for NaCl, HCl and \(\mathrm{CH_3COONa }\) are 126.4, 425.9, and 91.05 S cm2 mol–1 respectively. If the conductivity of 0.001028 mol L–1 acetic acid solution is \(4.95 \times 10^{-5} S ~cm^{-1} \), the degree of dissociation of the acetic acid solution is:
1. 0.01233
2. 1.00
3. 0.1233
4. 1.233

Subtopic:  Conductance & Conductivity |
 59%
Level 3: 35%-60%
NEET - 2022
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Two half cell reactions are given below:
\(\begin{aligned} &\mathrm{{Co}^{3+}+e^{-} \rightarrow {Co}^{2+}, {E}_{{Co}^{2+} / {Co}^{3+}}^{\circ}=-1.81 {~V}} \\ &2 \mathrm{{Al}^{3+}+6 e^{-} \rightarrow 2 {Al}({s}), {E}_{{Al} / {Al}^{3+}}^{\circ}=+1.66 {~V}} \end{aligned} \)
The standard EMF of a cell with feasible redox reaction will be:

1. +7.09 V 2. +0.15 V
3. +3.47 V 4. –3.47 V
Subtopic:  Electrode & Electrode Potential |
 69%
Level 2: 60%+
NEET - 2022
Hints

Standard electrode potential for the cell with cell reaction
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
is 1.1 V. Calculate the standard Gibbs energy change for the cell reaction. (Given F = 96487 C mol–1)
1. –200.27 kJ mol–1 2. –212.27 kJ mol–1
3. –212.27 J mol–1 4. –200.27 J mol–1
Subtopic:  Relation between Emf, G, Kc & pH |
 82%
Level 1: 80%+
NEET - 2022
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Given below are two statements:
Assertion (A): In the equation, \(\Delta_{\mathrm{r}} \mathrm{G}=-\mathrm{nFE} _{\text {cell }}, \) value of \(\mathrm{\Delta_rG }\) depends on n. 
Reason (R): \(\mathrm{E_{cell} }\) is an intensive property and \(\mathrm{\Delta_rG }\)  is an extensive property. 
 
1. (A) is False but (R) is True. 
2. Both (A) and (R) are True and (R) is the correct explanation of (A)
3. Both (A) and (R) are True and (R) is not the correct explanation of (A)
4. (A) is True but (R) is False.
Subtopic:  Relation between Emf, G, Kc & pH |
 59%
Level 3: 35%-60%
NEET - 2023
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