Electro chemistry practice · Medium

Assertion: When aqueous sodium chloride solution is electrolysed, Oxygen gas is produced at the anode.

Reason: It is due to the overpotential for oxidation of water to oxygen.

The EMFs of the cell obtained by combining separately $\mathrm{Zn}$ and $\mathrm{Cu}$ electrodes of a Daniel cell with normal calomel electrodes are $1.083 \mathrm{~V}$ and $-0.018 \mathrm{~V},$ respectively, at $25^{\circ} \mathrm{C}.$ If the potential of normal calomel electrode is $-0.28 \mathrm{~V},$ the EMF of the Daniel cell is

The electrode potential of the following half-cell at $298 \mathrm{~K}$
$X\left|X^{+2}(0.1 M)\right|\left|Y^{+2}(0.001 M)\right| Y$ is ____ $\times 10^{-2} \mathrm{~V}$ (Nearest integer) given $E^0 X^{+2} / X=-1.58 \mathrm{~V} E^0 Y^{+2} / Y=+0.74, \frac{2.303 R T}{F}=0.06 \mathrm{~V}$

The resistance of $0.05 \mathrm{~N}$ solution of an electrolyte was found to be $420 \mathrm{~ohm}$ at $298 \mathrm{~K}$. Its conductance is

Given, $E_{C{l_2}/C{l^ - }}^\mathrm{o} = 1.36\,V,\,E_{C{r^{3 + }}/Cr}^\mathrm{o} = - 0.74\,V$
$E_{C{r_2}O_7^{2 - }/C{r^{3 + }}}^\mathrm{o} = 1.33\,V,\,E_{MnO_4^ - /M{n^{2 + }}}^\mathrm{o} = 1.51\,V$
Among the following, the strongest reducing agent is

Select the correct statement(s) for the weak electrolyte.

An object whose surface area is $80 \mathrm{~cm}^2$ is to be plated with an even layer of gold $8.0 \times 10^{-4} \mathrm{~cm}$ thick. The density of gold is $19.7 \mathrm{~g} / \mathrm{cm}^3.$ The object is placed in a solution of $\mathrm{Au}\left(\mathrm{NO}_3\right)_3$ and a current of $\text{2.4 A}$ is applied. The time required for the electroplating to be completed, assuming that the layer of gold builds up evenly, is $(\mathrm{Au}=197)$

${E^ \circ }$ values of $M{g^{(2 + )}}$ / Mg is -2.37 V, of $\mathrm{Z}{\mathrm{n}^{2 + }}$ / Zn is -0.76 V and $\mathrm{F}{\mathrm{e}^{2 + }}$ / Fe is -0.44 V.
Which of the statements is correct?

Hydrogen gas is not liberated when the following metal is added to dil. HCl

For given cell, $\mathrm{Mg} / \mathrm{Mg}^{2+}(0.01 \mathrm{M}) \| \mathrm{Ag}^{+}(0.01 \mathrm{M}) / \mathrm{Ag}$, if $\mathrm{E}_{\text {cel }}^{\circ}=3.17 \mathrm{~V}$, then $\mathrm{E}_{\text {cell }}$ will be

A certain current liberates 0.504 g of hydrogen in 2 hr. How many gram of copper can be liberated by the same current flowing for the same time in $\mathrm{CuS}{\mathrm{O}_4}$ solution?

Which process occurs in the electrolysis of aqueous solution of nickel chloride at nickel anode?

Statement I: on dilution of the solution the electrode potential increases

Statement II: Effect of dilution on electrode potential depends on electrode whether it is metal or non-metal

Assertion (A): In weak electrolytes, the change in $\Lambda_{\mathrm{m}}$ with dilution is mainly due to increase in degree of dissociation
Reason (R): At a given concentration of weak electrolyte the degree of dissociation $\alpha=\frac{\Lambda_{\mathrm{m}}^0}{\Lambda_{\mathrm{m}}}$

Assertion: Sodium ions are discharged at the $\mathrm{Hg}$ electrode during electrolysis in preference to $\mathrm{H}^{+}$ions.

Reason: The nature of electrode also affects the order of discharge of cations.

The conductivity of a $0.1N{\kern 1pt} \mathrm{KCl}$ solution at 230C is 0.012 $\mathrm{oh}{\mathrm{m}^{ - 1}}{\kern 1pt}{\kern 1pt}\mathrm{c}{\mathrm{m}^{ - 1}}$ .The resistance of the cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be :

The quantity of charge required to completely reduce $0.5 \mathrm{~mol}$ of $\mathrm{MnO}_4^{-}$to $\mathrm{Mn}_2 \mathrm{O}_3$ is

The ${E^ \circ }$ of $\mathrm{F}{\mathrm{e}^{2 + }}/\mathrm{Fe}$ and $\mathrm{S}{\mathrm{n}^{2 + }}/\mathrm{Sn}$ are -0.44 V and -0.14 V respectively. If cell reaction is

$\mathrm{Fe} + \mathrm{S}{\mathrm{n}^{2 + }} \to \mathrm{F}{\mathrm{e}^{2 + }} + \mathrm{Sn}$

then emf of the cell is

A 4.0 molar aqueous solution of $\mathrm{NaCl}$ is prepared and $500 \mathrm{~mL}$ of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrodes. If the cathode is a $\mathrm{Hg}$ electrode, the maximum weight $(\mathrm{g})$ of amalgam $(\mathrm{Na}-\mathrm{Hg})$ formed from this solution is : (atomic mass: $\mathrm{Na}=23, \mathrm{Hg}=200$ )

A solution is 1 molar in each of ${NaCl}, {CdCl}_2,{ZnCl}_2$ and ${PbCl}_2$. To this ${Sn}$ metal is added, which of the following is true?
$\left[\begin{array}{l} \text { Given } \quad {E}^{\circ}\left({Pb}^{2+} /{Pb}=-0.126 \mathrm{~V}\right) \\ {E}_{{Sn}^2 /{Sn}}^{\circ}=-0.136 \mathrm{~V},{E}_{{Cd}^{2+} / {Cd}}^{\circ}=-0.40 \mathrm{~V} \\ {E}_{{Zn}^{2+} / {Zn}}^{\circ}=-0.763 \mathrm{~V}, {E}_{{Na}^{+} /{Na}}^{\circ}=-2.71 \mathrm{~V} \end{array}\right]$

The equivalent conductivity of 0.1 M weak acid is 100 times less than that at infinite dilution. The degree of dissociation of weak electrolyte at 0.1 M is :

A certain quantity electricity is passed through aqueous solutions of $A{l_2}{(S{O_4})_3}$ and $CuS{O_4}$ solutions connected in series. 0.09 g of $Al$ is deposited on cathode during electrolysis. The amount of copper deposited on cathode in grams is (Atomic weight of $Al = 27$, Atomic weight of $Cu = 63.6$)

The resistance of $2.5 \mathrm{~N}$ solution of acetic acid is $230 \mathrm{~ohm}$, when measured in a cell having a cell constant of $1.15 \mathrm{~cm}^{-1}$. The equivalent conductance is $\mathrm{ohm}^{-1} \mathrm{~cm}^2$ equiv ${ }^{-1}$

The standard reduction potential of $\mathrm{E}_{\mathrm{Bi}^3}^{3+} / \mathrm{Bi}$ and $\mathrm{E}_{\mathrm{Cu}^{2+} / \mathrm{Cu}}$ are $0.226 \mathrm{~V}$ and $0.344 \mathrm{~V}$ respectively $\mathrm{A}$ mixture of salts of $\mathrm{Bi}$ and $\mathrm{Cu}$ at unit concentration each is electrolysed at $25^{\circ} \mathrm{C}$. To what value can $\left[\mathrm{Cu}^{2+}\right]$ be brought down before bismuth starts to deposit during electrolysis.

During the electrolysis of $0.1 \mathrm{~M}-\mathrm{CuSO}_4$ solution using copper electrodes, a depletion of $\mathrm{Cu}^{2+}$ occurs near the cathode with a corresponding excess near the anode, owing to inefficient stirring of the solution. If the local concentration of $\mathrm{Cu}^{2+}$ near the anode and cathode are, respectively, $0.12 \mathrm{~M}$ and $0.08 \mathrm{~M},$ the back EMF developed at $298 \mathrm{~K}$ is $(\log 1.5=0.18,2.303 R T / F=0.06)$

Resistivity of a material is equal to resistance when cell
constant is

Which of the following statements is correct? Galvanic cell converts:

Assertion (A) $E_{\text {cell }}$ increases with increase in concentration of $\mathrm{Ag}^{+}$ions.

Reason (R) $E_{\text {cell }}$ has positive value.

12.3 g nitrobenzene is reduced into aniline by electrolysis, if current efficiency is 25% calculate charge required in coulombs

Assertion: In electrolytic refining, electrolytic cell consists of pure and impure Cu electrodes dipped in $\mathrm{CuSO}_4(\mathrm{ag})$.

Reason: Pure cu is obtained at anode.