Embibe Experts Solutions for Chapter: Electrochemistry, Exercise 2: EXERCISE-2

What a lead storage is discharged :-

$\mathrm{Fe}$ is reacted with $1.0\mathrm{MHCl}.\mathrm{E}°$ for $\mathrm{Fe}/{\mathrm{Fe}}^{2+}=+0.34 \mathrm{volt}.$ The correct observation $\left(\mathrm{s}\right)$ regarding this reaction is/are :-

Salts of $\mathrm{A}$ (atomic weight $=7), \mathrm{B}$ (atomic weight $=27)$ and $\mathrm{C}$ (atomic weight $=48)$ were electrolysed under identical conditions using the same quantity of electricity. It was found that when $2.1 \mathrm{g}$ of $\mathrm{A}$ was deposited, the weights of $\mathrm{B}$ and $\mathrm{C}$ deposited were $2.7 \mathrm{g}$ and $7.2 \mathrm{g}.$ The valencies of $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ respectively are :-

During electrolysis of an aqueous solution of ${\mathrm{CuSO}}_4$ using copper electrodes, if $2.5 \mathrm{g}$ of $\mathrm{Cu}$ is deposited at cathod, then at anode :-

A silver wire dipped in $0.1 \mathrm{M} \mathrm{HCl}$ solution saturated with $\mathrm{AgCl}$ develops a potential of $-0.25 \mathrm{V}.$ If ${{\mathrm{E}}^{°}}_{\frac{\mathrm{Ag}}{{\mathrm{Ag}}^{+}}}=-0.799 \mathrm{V},$ the ${\mathrm{K}}_{\mathrm{sp}}$ of $\mathrm{AgCl}$ in pure water will be :-

Consider the reaction of extraction of gold from its ore

$\mathrm{Au}+2{\mathrm{CN}}^{-}(\mathrm{aq}.) +\frac{1}{4}{\mathrm{O}}_2( \mathrm{g})+\frac{1}{2}{\mathrm{H}}_2\mathrm{O}⟶\mathrm{Au}(\mathrm{CN}{)}_2^{-}+{\mathrm{OH}}^{-}$

Use the following data to calculate $\Delta \mathrm{G}^{\circ}$ for the reaction

${\mathrm{K}}_{\mathrm{f}}\left\{\mathrm{Au}(\mathrm{CN}{)}_2^{-}\right\}=\mathrm{X}$

$\begin{array}{ccc}{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{e}}^{-}⟶4{\mathrm{OH}}^{-}& :& \mathrm{E}°=+0.41 \mathrm{volt}\\ {\mathrm{Au}}^{3+}+3{\mathrm{e}}^{-}⟶\mathrm{Au}& :& \mathrm{E}°=+1.5 \mathrm{volt}\\ {\mathrm{Au}}^{3+}+2{\mathrm{e}}^{-}⟶{\mathrm{Au}}^{+}& :& \mathrm{E}°=+1.4 \mathrm{volt}\end{array}$

For the fuel cell reaction $2{\mathrm{H}}_2 \left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)⟶2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right); {\mathrm{\Delta }}_{\mathrm{f}}{\mathrm{H}}_{298}^{\mathrm{o}}\left({\mathrm{H}}_2\mathrm{O}, \mathrm{l}\right)=\frac{-285.5 \mathrm{kJ}}{\mathrm{mol}}$ What is $\mathrm{\Delta S}{°}_{298}$ for the given fuel cell reaction ?

Given : ${\mathrm{O}}_2\left(\mathrm{g}\right)+4{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+4{\mathrm{e}}^{-}⟶2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \mathrm{E}°=1.23 \mathrm{V}$

The dissociation constant of $\mathrm{n}-$butyric acid is $1.6\times {10}^{-5}$ and the molar conductivity at infinite dilution is $380\times {10}^{-4}{\mathrm{Sm}}^2{ \mathrm{mol}}^{-1}.$ The specific conductance of the $0.01\mathrm{M}$ acid solution is :-