(B) The cell reaction is: $QH_2 + 2Ag^+ \rightarrow Q + 2Ag + 2H^+$. $E^o_{\text{cell}} = E^o_{Ag^+/Ag} - E^o_{Q/QH_2} = 0.8 - 0.7 = 0.1 \ V$. Using t

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(B) The cell reaction is: $QH_2 + 2Ag^+ \rightarrow Q + 2Ag + 2H^+$. $E^o_{\text{cell}} = E^o_{Ag^+/Ag} - E^o_{Q/QH_2} = 0.8 - 0.7 = 0.1 \ V$. Using the Nernst equation: $E_{\text{cell}} = E^o_{\text{cell}} - \frac{0.06}{2} \log \frac{[H^+]^2}{[Ag^+]^2}$. Given $E_{\text{cell}} = 0.4 \ V$,$[Ag^+] = 1 \ M$: $0.4 = 0.1 - 0.03 \log [H^+]^2 = 0.1 - 0.06 \log [H^+]$. $0.3 = -0.06 \log [H^+]$ $\Rightarrow \log [H^+] = -5$ $\Rightarrow pH = 5$. For a salt of a weak base and strong acid $(NH_4X)$,$pH = 7 - \frac{1}{2} pK_b - \frac{1}{2} \log C$. $5 = 7 - \frac{1}{2} pK_b - \frac{1}{2} \log (0.01)$. $5 = 7 - \frac{1}{2} pK_b - \frac{1}{2} (-2) = 7 - \frac{1}{2} pK_b + 1 = 8 - \frac{1}{2} pK_b$. $\frac{1}{2} pK_b = 3 \Rightarrow pK_b = 6$.

Class 12 Chemistry Electrochemistry Mix Examples-Electrochemistry

Difficult

Consider the following electrochemical cell at standard condition: $Au_{(s)} | QH_2, Q | NH_4X(0.01 \ M) || Ag^{+}(1 \ M) | Ag_{(s)}$. Given $E_{\text{cell}} = +0.4 \ V$. The couple $QH_2 / Q$ represents the quinhydrone electrode,and the half-cell reaction is given as: $Q + 2e^- + 2H^+ \rightarrow QH_2$ with $E^o_{Q/QH_2} = +0.7 \ V$. Given: $E^o_{Ag^+/Ag} = +0.8 \ V$ and $\frac{2.303 \ RT}{F} = 0.06 \ V$. The $pK_b$ value of the ammonium halide salt $(NH_4X)$ used here is $.........$ (nearest integer).

JEE MAIN 2025 All JEE MAIN

A
$5$
B
$6$
C
$16$
D
$9$

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For lead storage battery,pick the correct statements:
$A.$ During charging of battery,$PbSO_4$ on anode is converted into $Pb$.
$B.$ During charging of battery,$PbSO_4$ on cathode is converted into $PbO_2$.
$C.$ Lead storage battery consists of a grid of lead packed with $PbO_2$ as cathode.
$D.$ Lead storage battery has $\sim 38\%$ solution of sulphuric acid as an electrolyte.
Choose the correct answer from the options given below:

MediumJEE MAIN 2023

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The molar conductivity of $0.025 \ mol \ L^{-1}$ methanoic acid is $46.1 \ S \ cm^2 \ mol^{-1}$. Calculate its degree of dissociation and dissociation constant. Given $\lambda^o(H^{+}) = 349.6 \ S \ cm^2 \ mol^{-1}$ and $\lambda^o(HCOO^{-}) = 54.6 \ S \ cm^2 \ mol^{-1}$.

Difficult

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Given below are the half-cell reactions:
$Mn^{2+} + 2e^{-} \rightarrow Mn; E^{o} = -1.18 \ V$
$2(Mn^{3+} + e^{-} \rightarrow Mn^{2+}); E^{o} = +1.51 \ V$
The $E^{o}$ for $3Mn^{2+} \rightarrow Mn + 2Mn^{3+}$ will be:

DifficultJEE MAIN 2014

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The molar conductance of $NaCl$,$HCl$,and $CH_{3}COONa$ at infinite dilution are $126.45$,$426.16$,and $91.0 \ S \ cm^{2} \ mol^{-1}$ respectively. The molar conductance of $CH_{3}COOH$ at infinite dilution is. Choose the right option for your answer. (In $S \ cm^{2} \ mol^{-1}$)

EasyNEET 2021

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Match List-$I$ with List-$II$.

List-$I$ (Conversion) List-$II$ (Number of Faraday required)

$A$. $1 \ mol$ of $H_2O$ to $O_2$ $I$. $3 \ F$

$B$. $1 \ mol$ of $MnO_4^{-}$ to $Mn^{2+}$ $II$. $2 \ F$

$C$. $1.5 \ mol$ of $Ca$ from molten $CaCl_2$ $III$. $1 \ F$

$D$. $1 \ mol$ of $FeO$ to $Fe_2O_3$ $IV$. $5 \ F$

Choose the correct answer from the options given below:

MediumNEET 2024

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List-$I$ (Conversion)	List-$II$ (Number of Faraday required)
$A$. $1 \ mol$ of $H_2O$ to $O_2$	$I$. $3 \ F$
$B$. $1 \ mol$ of $MnO_4^{-}$ to $Mn^{2+}$	$II$. $2 \ F$
$C$. $1.5 \ mol$ of $Ca$ from molten $CaCl_2$	$III$. $1 \ F$
$D$. $1 \ mol$ of $FeO$ to $Fe_2O_3$	$IV$. $5 \ F$

Similar Questions

The molar conductivity of $0.025 \ mol \ L^{-1}$ methanoic acid is $46.1 \ S \ cm^2 \ mol^{-1}$. Calculate its degree of dissociation and dissociation constant. Given $\lambda^o(H^{+}) = 349.6 \ S \ cm^2 \ mol^{-1}$ and $\lambda^o(HCOO^{-}) = 54.6 \ S \ cm^2 \ mol^{-1}$.

Given below are the half-cell reactions:$Mn^{2+} + 2e^{-} \rightarrow Mn; E^{o} = -1.18 \ V$$2(Mn^{3+} + e^{-} \rightarrow Mn^{2+}); E^{o} = +1.51 \ V$The $E^{o}$ for $3Mn^{2+} \rightarrow Mn + 2Mn^{3+}$ will be:

The molar conductance of $NaCl$,$HCl$,and $CH_{3}COONa$ at infinite dilution are $126.45$,$426.16$,and $91.0 \ S \ cm^{2} \ mol^{-1}$ respectively. The molar conductance of $CH_{3}COOH$ at infinite dilution is. Choose the right option for your answer. (In $S \ cm^{2} \ mol^{-1}$)

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Given below are the half-cell reactions:
$Mn^{2+} + 2e^{-} \rightarrow Mn; E^{o} = -1.18 \ V$
$2(Mn^{3+} + e^{-} \rightarrow Mn^{2+}); E^{o} = +1.51 \ V$
The $E^{o}$ for $3Mn^{2+} \rightarrow Mn + 2Mn^{3+}$ will be: