Electro chemistry practice · Mixed difficulty

STATEMENT-1 : We cannot add the electrode potential in order to get electrode potential of third electrode if no. of moles of electrons exchanged are not same.
STATEMENT-2 : Electrode potential is an extensive property.

Which of the following reactions occurs at the cathode?

The potential difference of two electrodes in a galvanic cell is known as

What is the density of solution of sulphuric acid used as on electrolyte in lead accumulator

A depolariser used in dry cell batteries is :

The standard potentials of ${OCl}^{-} / {Cl}^{-}$ and ${Cl}^{-} / {Cl}_2$ are $0.94 \mathrm{~V}$ and $-1.36 \mathrm{~V},$ respectively. The $E^{\circ}$ value of ${OCl}^{-} / {Cl}_2$ will be

The resistance of 1N solution of acetic is 250Ω ,when measured in a cell having a cell constant of $1.15{\kern 1pt} {\kern 1pt}\mathrm{c}{\mathrm{m}^{ - 1}}$ .The equivalent conduction (in $\mathrm{oh}{\mathrm{m}^{ - 1}}{\kern 1pt} {\kern 1pt}\mathrm{c}{\mathrm{m}^2}{\kern 1pt} {\kern 1pt}\mathrm{equi}{\mathrm{v}^{ - 1}}$ ) of 1N acetic acid is

An alloy of Pb-Ag weighing 1.08 g was dissolved in dilute $\mathrm{HN}{\mathrm{O}_3}$ and the volume made to 100 mL. A silver electrode was dipped in the solution and the emf of the cell set up
$\mathrm{Pt}\left( s \right),{\mathrm{H}_2}\left( g \right)\left| {{\mathrm{H}^ + }\left( {1\mathrm{M}} \right)} \right|\left| {\mathrm{A}{\mathrm{g}^ + }\left( {aq} \right)} \right|\mathrm{Ag}\left( s \right)$
Was 0.62 V. If $E_{\mathrm{cell}}^ \circ$ = 0.80 V, what is the percentage of Ag in the alloy?
[At ${25^ \circ }C$ , RT /F = 0.06]

Two platinum electrodes were immersed in a solution of cupric sulphate and electric current passed through the solution. After sometime, it was found that the colour of copper sulphate disappeared with evolution of gas at the electrode. The colourless solution contains:

Statement I: In case of $\mathrm{Hg}$ cathode $\mathrm{Na}$ undergoes deposition
Statement II: Nature of electrode determines the deposition order

Lithium is generally used as an electrode in high energy density batteries. This is because:

The conductivity of $N/50$ solution of $\mathrm{KCl}$ in a cell at 250C is $0.002765{\kern 1pt} {\kern 1pt} {\rm{mho {\kern 1pt}{\kern 1pt} c}}{\mathrm{m}^{ - 1}}$ . If the resistance of a cell containing this solution is 400 ohm, the cell constant is :

Which one of the following solutions has highest conductance power?

If ϕ denotes standard reduction potential, which is true:

For the given reactions

$\mathrm{S n}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{S n}$

$\mathrm{S n}^{4+}+2 \mathrm{e}^{-} \rightarrow \mathrm{S n}$

The electrode potentials are; $\mathrm{E}_{\mathrm{Sn}^{2+} / \mathrm{Sn}}^0=-0.140\text{ V}$ and $\mathrm{E}_{\mathrm{Sn}^{4+} / \mathrm{Sn}}^{\circ}=0.010 \mathrm{~V}.$ The magnitude of standard electrode potential for $\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}$ i.e. $\mathrm{E}_{\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}}$ is _____ $\times{10^{-{2}} \mathrm{V}}.$

If ${E}_{{Cu}^{2+} / {Cu}}^{\circ}=+0.34 \,{~V}$ then reduction potential of ${Cu}^{2+} / {Cu}$ electrode at ${pH}=14$ is $\left({K}_{{sp}}\right.$ of ${Cu}({OH})_2=1$ $\times 10^{-19}$ )

Calculate the volume of ${\mathrm{H}_2}$ gas at NTP obtained by passing 4 A through acidified ${\mathrm{H}_2}\mathrm{O}$ for 30 min is

How much metal will be deposited when a current of 12 ampere with $75 \%$ efficiency is passed through the cell for $3 \mathrm{~h}$? (Given: ${Z}=4 \times 10^{-4}$)

For the galvanic cell

$\mathrm{Cr}(\mathrm{s})\left|\mathrm{Cr}^{3+}\left(2.23 \times 10^{-7} \mathrm{M}\right) \| \mathrm{Ag}^{+}(0.0264 \mathrm{M})\right| \mathrm{Ag}(\mathrm{s})$ at $25^{\circ} \mathrm{C}$

Calculate the emf of the cell.

Given: $\mathrm{E}^{\circ}\left(\mathrm{Ag}^{+} / \mathrm{Ag}\right)=0.80 \mathrm{~V}$

$\mathrm{E}^{\circ}\left(\mathrm{Cr}^{+3} / \mathrm{Cr}\right)=-0.74 \mathrm{~V}$

Using a particular conductivity cell, resistance offered is $60 \Omega$. When the conductivity cell with area twice the earlier and having $75 \%$ more distance between the electrodes is used, resistance offered will be

On which factor, electrical conductivity of electrolytic cell doesn’t depend

During electrolysis of sulphuric acid, which of the following processes is possible at anode?

A. $2 {H}_2 {O}({l}) \longrightarrow {O}_2({~g})+4 {H}^{+}({aq})+4 {e}^{-} \stackrel{\ominus}{{E}_{\text {cell }}}=+1.23 {~V}$

B. $2 {SO}_4^{2-}({aq}) \longrightarrow {S}_2 {O}_8^{2-}({aq})+2 {e}^{-} \stackrel{\ominus}{{E}_{\text {cell }}}= 1.96 {~V}$

Choose the correct option based on following statements.

(i) Process A is preferred at higher concentration of sulphuric acid.

(ii) Process B is preferred at higher concentration of sulphuric acid.

(iii) Process A is preferred for dilute sulphuric acid.

(iv) Process B is preferred for dilute sulphuric acid.

(v) Both A and B are equally possible at higher concentration.

The amount of charge that must be passed through a solution containing $\mathrm{Cu}^{2+}$ in order to deposit $1 \mathrm{~g}$ atom of copper $(63.55)$ is

A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of 2.7 V. If the standard reduction potential of copper electrode is +0.34 V then that of the magnesium electrode is

The Gibbs energy change (in KJ) for the given reaction at $\left[ {C{u^{2 + }}} \right] = \left[ {S{n^{2 + }}} \right] = 1M$ and 298 K is $Cu\left( s \right) + S{n^{2 + }}\left( {aq} \right) \to C{u^{2 + }}\left( {aq} \right) + SN\left( s \right);\,\left( {E_{S{n^{2 + }}/Sn}^0 = - 0.16V,\,E_{C{u^{2 + }}/Cu}^0 = 0.34V} \right)$
Take, $F = 96500\,\,\,C\,\,mo{l^{ - 1}}$)

When an acid cell is charged, then

When a lead storage battery is charged

A student made the following observations in the laboratory,
i) Clean copper metal did not react with 1 molar $\mathrm{Pb}{\left( {\mathrm{N}{\mathrm{O}_3}} \right)_2}$ solution.
ii) Clean lead metal dissolved in a 1 molar $\mathrm{AgN}{\mathrm{O}_3}$ solution and crystals of $\mathrm{Ag}$ metal appeared.
iii) Clean silver metal did not react with 1 molar $\mathrm{Cu}{\left( {\mathrm{N}{\mathrm{O}_3}} \right)_2}$ solution.
The order of decreasing reducing character of the three metals is :

How much current is necessary to produce $\mathrm{H}_2$ gas at the rate of $1 \mathrm{~cm}^3$ per second under STP.

The standard emf for the cell reaction,

$2\mathrm{C}{\mathrm{u}^ + }\left( {aq} \right) \to 2\mathrm{Cu}\left( s \right) + \mathrm{C}{\mathrm{u}^ + }\left( {aq} \right)$

is +0.36 V at 298 K. The equilibrium constant of the reaction is