Electro chemistry practice · Medium

Which statement is not correct

In mercury cell electrolyte used is

Which of the following metals cannot be used as sacrificial electrode for iron?

Assertion: $\mathrm{pH}$ of solution increases during electrolysis of aqueous solution of $\mathrm{NaCl}$.

Reason: Electrolysis is non-spontaneous process.

In following cell reaction

${Mg}({s})+2 {Ag}^{+}(0.001 {M}) \longrightarrow {Mg}^{2+}(0.20 {M})+2 {Ag}({s})$

Calculate $E_{\text {cell }}$ for the reaction $\left[E^0=3.17 {~V}\right]$

Four successive members of the first row transition elements listed below with atomic numbers. Which one of them is expected to have the highest $E_{{M^{3 + }}/{M^{2 + }}}^ \circ$ value is?

If the molar conductivity of $10^{-3} \mathrm{~M} \mathrm{~HA}$ is $39 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1},$ then its dissociation constant will be

[Given $\Lambda_{\mathrm{m}}^0(\mathrm{HA})=390 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}]$

In acidic medium $\mathrm{MnO}_4^ -$ is converted to $\mathrm{M}{\mathrm{n}^{2 + }}$ . The quantity of electricity in faraday required to reduce 0.5 mole of $\mathrm{MnO}_4^ -$ to $\mathrm{M}{\mathrm{n}^{2 + }}$ would be

During the electrolysis of a solution of $\mathrm{AgN}{\mathrm{O}_3},9650\mathrm{C}$ of charge is passed through the electroplating bath.
The mass of silver deposited at the cathode will be

The equivalent conductance of an aqueous solution of $1.0283 \times 10^{-3} \mathrm{~g}$ equivalent acetic acid per litre is $48.15 \pi^{-1} \mathrm{~cm}^2$ equiv $^{-1}$ at $25^{\circ} \mathrm{C}$. At infinite dilution value is $390.7 \pi^{-1} \mathrm{~cm}^2$ equiv ${ }^{-1}$. Calculate the degree of ionisation and ionisation constant of acetic acid.

Which of the following electrolytes is used in lead storage battery?

On the basis of the information available from the $\frac{4}{3} \mathrm{Al}+\mathrm{O}_2 \longrightarrow \frac{2}{3} \mathrm{Al}_2 \mathrm{O}_3, \Delta G=-827 \mathrm{~kJ} \mathrm{~mol}^{-1}$ of $\mathrm{O}_2$, the minimum emf required to carry out an electrolysis of $\mathrm{Al}_2 \mathrm{O}_3$ is : $\left(\mathrm{F}=96500 \mathrm{~C} \mathrm{~mol}^{-1}\right.$ )

In a fuel cell hydrogen and oxygen react to produce electricity. In the process hydrogen gas is oxidised at the anode and oxygen at the cathode. If $67.2 \mathrm{~L}$ of $\mathrm{H}_2$ at STP react in 15 minutes, what is the average current produced ? If the entire current is used for electrodeposition of copper from copper (II) solution, how many grams of copper will be deposited ?

Anode reaction : $\mathrm{H}_2+2 \mathrm{OH}^{-} \longrightarrow 2 \mathrm{H}_2 \mathrm{O}+2 \mathrm{e}^{-}$

Cathode reaction: $\mathrm{O}_2+2 \mathrm{H}_2+2 \mathrm{e}^{-} \longrightarrow 4 \mathrm{OH}^{-}$

Select the correct statement(s) for the given reaction.

$\mathrm{Cu}(s)+2 \mathrm{Ag}^{+}(a q) \longrightarrow \mathrm{Cu}^{2+}(a q)+2 \mathrm{Ag}(s)$

The electrical conductivity of the flowing aqueous solutions is highest for:

$\mathrm{KCl}\left( {aq} \right)$ cannot be used as a salt bridge for the cell $\mathrm{Cu}\left( s \right)\left| {\mathrm{CuS}{\mathrm{O}_4}\left( {aq} \right)} \right|\left| {\mathrm{AgN}{\mathrm{O}_3}\left( {aq} \right)} \right|\mathrm{Ag}\left( s \right)$ because :

A galvanic cell : $\mathrm{Cu}\left|\mathrm{Cu}^{2+}\right|\left|\mathrm{Ag}^{+}\right| \mathrm{Ag}$ initially contains $1 \mathrm{~M}\mathrm{~Ag}^{+}$and $1 \mathrm{~M} \mathrm{~Cu}^{2+}$ ions. The cell potential after the passage of $9.65 \mathrm{~A}$ of current for $1 \mathrm{~h}$ will be ___ V.

Assertion (A): $\Lambda_m$ for weak electrolytes shows a sharp increase, when the electrolytic solution is diluted.

Reason (R): For weak electrolytes degree of dissociation increases with dilution of solution.

$2 \mathrm{MnO}_4^{-}+\mathrm{aH}^{+}+\mathrm{bH}_2 \mathrm{O}_2 \longrightarrow 2 \mathrm{Mn}^{+2}+\mathrm{cH}_2 \mathrm{O}+\mathrm{dO}_2$. What are the values of $\mathrm{a}, \mathrm{b}, \mathrm{c}$ and $\mathrm{d}$?

The correct order of molar conductance at infinite dilution of ${NaCl}, {KCl}, {RbCl}$ is

$\mathrm{KCl}\left( {aq} \right)$ cannot be used as a salt bridge for the cell $\mathrm{Cu}\left( s \right)\left| {\mathrm{CuS}{\mathrm{O}_4}\left( {aq} \right)} \right|\left| {\mathrm{AgN}{\mathrm{O}_3}\left( {aq} \right)} \right|\mathrm{Ag}\left( s \right)$ because :

Following is the concentration cell in which electrode is
reversible with respect to anion
$\mathop {Pt\left( {C{l_2}} \right)}\limits_{1\,\,{\text{bar}}} \left| {C{l^ - }\left( {{C_1}} \right)} \right|\left| {C{l^ - }\left( {{C_2}} \right)} \right|\mathop {Pt\left( {C{l_2}} \right)}\limits_{1\,\,{\text{bar}}}$
The cell reaction is spontaneous, if

Assertion: The cell constant of a cell depends upon the nature of the material of the electrodes.

Reason: The observed conductance depends upon the nature of the electrolyte and the concentration of the solution.

Red hot carbon will remove oxygen from the oxides XO, and YO but not from ZO. Y will remove oxygen from XO. Use this evidence to reduce the order of activity of the three metals X, Y and Z putting the most reactive first:

The charge required to deposit $40.5 \mathrm{~g}$ of $\mathrm{Al}$ (atomic mass $=27.0 \mathrm{~g}$) from the fused $\mathrm{Al}_2\left(\mathrm{SO}_4\right)_3$ is:

For complete reduction of 1 mole of nitrobenzene to aniline, charge needed will be ( $F$ represents Faraday's constant)

Statement I: At the end of electrolysis using platinum electrodes an aqueous solution of copper sulphate turns colourless

Statement II: Copper in $\mathrm{CuSO}_4$ is converted to $\mathrm{Cu}(\mathrm{OH})_2$ during electrolysis

The ${\mathrm{\Lambda }^\infty }$ of $\mathrm{N}{\mathrm{H}_4}\mathrm{OH}$ at infinite dilution is …$S{\kern 1pt} {\kern 1pt} \mathrm{c}{\mathrm{m}^2}\mathrm{eq}{\mathrm{.}^{ - 1}}$ .Given $\lambda _{\mathrm{O}{\mathrm{H}^ - }}^\infty = 174,\lambda _{\mathrm{C}{\mathrm{l}^ - }}^\infty = 66$ and $\lambda _{\mathrm{N}{\mathrm{H}_4}\mathrm{Cl}}^\infty = 130{\kern 1pt} {\kern 1pt} {\rm{S {\kern 1pt} {\kern 1pt}c}}{\mathrm{m}^2}{\kern 1pt} {\kern 1pt}\mathrm{e}{\mathrm{q}^{ - 1}}:$

Calculate the electrode potential of given electrode at $25^{\circ} {C}$

${Pt} / {H}_2 / {H}^{+}({pH}=6)$

Statement I: A negative value of standard reduction potential means that reduction takes place on this electrode with reference to standard hydrogen electrode.

Statement II: The standard electrode potential of a half-cell has fixed value.