Embibe Experts Solutions for Chapter: Electrochemistry, Exercise 5: Exercise-5

Find out the volume of gases evolved by passing $0.965 \mathrm{A}$ current for $1\mathrm{hr}$ through an aqueous solution of ${\mathrm{CH}}_3\mathrm{COONa}$ at $25°\mathrm{C}$ and $1 \mathrm{atm}$.

At equimolar concentrations of ${\mathrm{Fe}}^{2+}$ and ${\mathrm{Fe}}^{3+}$, what must $\left[{\mathrm{Ag}}^{+}\right]$ be so that the voltage of the galvanic cell from the $\left({\mathrm{Ag}}^{+}\mid \mathrm{Ag}\right)$ and $\left({\mathrm{Fe}}^{3+}\mid {\mathrm{Fe}}^{2+}\right)$ electrodes equals zero?

${\mathrm{Fe}}^{2+}+{\mathrm{Ag}}^{+}\rightleftharpoons {\mathrm{Fe}}^{3+}+\mathrm{Ag}$,

${\mathrm{E}}_{{\mathrm{Ag}}^{+}\mid \mathrm{Ag}}=0.7991; {\mathrm{E}}_{{\mathrm{Fe}}^{3+}\mid {\mathrm{Fe}}^{2+}}=0.771$

The cell $Pt\left({\mathrm{H}}_2\right)\left(1 \mathrm{atm}\right)\left|{\mathrm{H}}^{+}\left(\mathrm{pH}=?\right)\Vert {\mathrm{I}}^{-}\left(\mathrm{a}=1\right)\right|\mathrm{AgI}\left(\mathrm{s}\right)$, $\mathrm{Ag}$ has $\mathrm{emf}$, ${\mathrm{E}}_{298 \mathrm{K}}=0$. The standard electrode potential for the reaction $\mathrm{AgI}+{\mathrm{e}}^{-}⟶\mathrm{Ag}+{\mathrm{I}}^{\mathrm{\Theta }}$ is $-0.151 \mathrm{volt}$. Calculate the $\mathrm{pH}$ value.

The specific conductivity of a saturated solution of $\mathrm{AgCl}$ is $3.40\times {10}^{-6} {\mathrm{ohm}}^{-1} {\mathrm{cm}}^{-1}$ at $25°\mathrm{C}$. If ${\mathrm{\lambda }}_{{\mathrm{Ag}}^{+}}=62.3 {\mathrm{ohm}}^{-1} {\mathrm{cm}}^2 {\mathrm{mol}}^{-1} \& {\mathrm{\lambda }}_{{\mathrm{Cl}}^{-}}=67.7 {\mathrm{ohm}}^{-1} {\mathrm{cm}}^2 {\mathrm{mol}}^{-1}$, the solubility of $\mathrm{AgCl}$ at $25°\mathrm{C}$ is:

Consider the reaction: $\left(\mathrm{T}=298 \mathrm{K}\right)$

${\mathrm{Cl}}_2\left(\mathrm{g}\right)+2{\mathrm{Br}}^{-}\left(\mathrm{aq}\right)⟶2{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)+{\mathrm{Br}}_2\left(\mathrm{aq}\right)$

Determine the emf (in volts) of the cell, when $\left[{\mathrm{Cl}}^{-}\right]=\left[{\mathrm{Br}}_2\right]=\left[{\mathrm{Br}}^{-}\right]=0.01 \mathrm{M}$ and ${\mathrm{Cl}}_2$ gas is at $1 \mathrm{atm}$ pressure.

($\mathrm{E}°$ for the above reaction is $=0.29$ volt)

Enter only the numerical value in the box  and exclude the units.

The oxidation potentials of$\mathrm{Zn}, \mathrm{Cu}, \mathrm{Ag}, {\mathrm{H}}_2$ and $\mathrm{Ni}$ are $0.76, -0.34, -0.80, 0.00, 0.25 \mathrm{volt},$ respectively. Which of the following reactions will provide maximum voltage?

A silver coulomb meter is in series with a cell electrolyzing water. In a time of $1 \mathrm{minute}$1 minute at a constant current,$1.08 \mathrm{g}$ silver got deposited on the cathode of the coulometer. What total volume $(\mathrm{In} \mathrm{mL})$ of the gases would have produced in other cell if in this cell the anodic and cathodic efficiencies were $90\%$ and $80\%$ respectively. Assume $\mathrm{STP}$ conditions and the gases collected are dry. $(\mathrm{Ag}-108)$ (Molar volume of any ideal gas at $\mathrm{STP}=22.4 \mathrm{L}$. Report as (your answer $÷10.)$

Peroxodisulphate salts $\left({\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_8\right)$ are strong oxidizing agents used as bleaching agents for fats, oil etc. 
Given

$\begin{array}{ll}{\mathrm{O}}_2\left(\mathrm{g}\right)+4{\mathrm{H}}^{\oplus }\left(\mathrm{aq}\right)+4{\mathrm{e}}^{-}⟶2{\mathrm{H}}_2\mathrm{O}\left(\ell \right)& \mathrm{E}°=1.23\mathrm{V}\end{array}$

$\begin{array}{ll}{\mathrm{S}}_2{\mathrm{O}}_8^{-2}+2{\mathrm{e}}^{-}⟶2{\mathrm{SO}}_4^{-2}\left(\mathrm{aq}\right)& \mathrm{E}°=2.01\mathrm{V}\end{array}$

Which of the following statements is (are) correct?