Electro chemistry practice · Mixed difficulty

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 cell in which electric current is produced by net oxidation and reduction process is called :

Statement-I: The voltage of mercury cell remains constant for long period of time.

Statement - II: The net cell reaction does not involve active species(ions) .

Among the following correct statements

I) Oxidising power $\propto \,\mathrm{SRP}\, \propto \frac{1}{{SOP}}$

II) Oxidising power $\propto$ SOP $\propto \frac{1}{{SOP}}$

III) Reducing power $\propto$ SOP $\propto \,\,\mathrm{SOP}\, \propto \,\frac{1}{{SRP}}$
IV) Reducing power $\propto$ SRP $\propto \frac{1}{{SOP}}$

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 correct order of electro chemical equivalent (e) of Sodium, Magnesium and Aluminium is

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 ${ }^{-1}$

Specific conductance of $10^{-4} \mathrm{~M} \mathrm{n}$-Butyric acid aqueous solution is $1.9 \times 10^{-9} \mathrm{~S} \mathrm{~m}^{-1}.$ If molar conductance of $\text{n}$-Butyric acid at infinite dilution is $380 \times 10^{-} \mathrm{S} \mathrm{m}^2 \mathrm{~mol}^1,$ then $\mathrm{K}_\text{a}$ for $\mathrm{n}$-Butyric acid is:

In which case $\left(E_{\text {cell }}-E_{\text {cell }}^{\circ}\right)$ is zero

Hydrogen-oxygen fuel cells are used in spacecraft to supply :

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.

The correct value of e.m.f. of cell is given by :

i) ${E_{cell}} = {E_{OP}}{\kern 1pt} anode - {E_{RP}}{\kern 1pt} cathode$

ii) ${E_{cell}} = {E_{OP}}{\kern 1pt} anode + {E_{RP}}{\kern 1pt} cathode$

iii) ${E_{cell}} = {E_{RP}}{\kern 1pt} anode + {E_{RP}}{\kern 1pt} cathode$

iv) ${E_{cell}} = {E_{OP}}{\kern 1pt} anode - {E_{OP}}{\kern 1pt} cathode$

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:

$100 \mathrm{~g} \mathrm{~Al}$ is to be deposited on the cathode of the electrolytic cell containing $\mathrm{Al}_2 \mathrm{O}_3$ in the solvent $\mathrm{Na}_3 \mathrm{AlF}_6$ by a current of $125 \mathrm{~A}$. If at the cathode, reaction is

$\mathrm{Al}^{3+}+3 e^{-} \longrightarrow \mathrm{Al}$

then time required for the passage of current is $(\mathrm{Al}=27)$

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

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

Pure water does not conduct electricity because it is

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

In electrolysis, oxidation takes place at:

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.

Which statement is not correct

In mercury cell electrolyte used is

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

The amount of electricity that can deposit 108 g of
silver from silver nitrate solution is

The charge required to liberate one gram equivalent of an element is

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

Reason: Electrolysis is non-spontaneous process.