Electro chemistry practice · Medium

Find weight of Zinc in Zinc sulphate electrolysis $\mathrm{i}=0.015 \mathrm{~A,t} =15$ minutes

Find the emf of the cell in which the following reaction takes place at 298 K
$Ni(s) + 2A{g^ + }(0.001M) \to N{i^{2 + }}(0.001M) + 2Ag(s)$
(Given that $E_{cell}^ \circ = 10.5\,V,\,\frac{{2.303\,RT}}{F} = 0.059$ at 298 K)

If the following half cells have the $E^{\circ}$ values as $\mathrm{Fe}^{3+}+e^{-} \rightarrow \mathrm{Fe}^{2+} ; E^{\circ}=+0.77 \mathrm{~V}$ and $\mathrm{Fe}^{2+}+2 e^{-} \rightarrow \mathrm{Fe} ; E^{\circ}=-0.44 \mathrm{~V};$ the $E^{\circ}$ of the half-cell $\mathrm{Fe}^{3+}+3 e^{-} \rightarrow \mathrm{Fe}$ will be

An electronic conductor is

The SRP values of the elements A, B and C are 0.68, -2.50 and 0.50V respectively. The order of their reducing power is

Without losing its concentration ${ZnCl}_2$ solution cannot be kept in contact with

Molar conductance of an electrolyte increases with dilution according to the equation.

$\Lambda_{\mathrm{m}}=\Lambda_{\mathrm{m}}^{\circ}-\mathrm{A} \sqrt{\mathrm{C}}$

Which of the following statement is/are true:

The molecular conductivity and equivalent conductivity are same for the solution of :

Calculate the standard Gibbs free energy of

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

The cell reaction of A cell is
$\mathrm{Mg}\left( s \right) + \mathrm{C}{\mathrm{u}^{2 + }}\left( {aq} \right) \to \mathrm{Cu}\left( s \right) + \mathrm{M}{\mathrm{g}^{2 + }}\left( {aq} \right)$
If the standard reduction potentials of Mg and Cu are – 2.37 and + 0.34 V respectively. The emf of the cell is

Charge required to liberate $11.5 \mathrm{~g}$ sodium is

Standard potentials $\left(E^{\circ}\right)$ for some half-reactions are given below:

(i) ${Sn}^{4+}+2 {e}^{-} \rightarrow {Sn}^{2+} ; E^{\circ}=+0.15 {~V}$

(ii) $2 {Hg}^{2+}+2 {e}^{-} \rightarrow {Hg}_2{ }^{2+} ; E^{\circ}=+0.92 {~V}$

(iii) ${PbO}_2+4 {H}^{+}+2 {e}^{-} \rightarrow {Pb}^{2+}+2 {H}_2 {O} ; E^{\circ}=+1.45 {~V}$

Based on the above, which one of the following statements is correct?

An electrochemical cell is constructed as:

${\text{Zn}}\left| {{\text{Z}}{{\text{n}}^{2 + }}(0.1{\text{M}})||{{\text{H}}^ + }({\text{XM}})} \right|\mathop {\left( {{{\text{H}}_2}} \right){\text{Pt}}}\limits_{1\,{\text{bar}}} {\text{; E}}_{{\text{Z}}{{\text{n}}^{2 + }}\mid {\text{Zn}}}^0 = - 0.76\;{\text{V}}$

If emf of cell is $0.17 \mathrm{~V}$ then $\mathrm{pH}$ of cathodic compartment is:

Assertion:The electrode potential of SHE is zero.

Reason: SHE is a standard reference electrode.

An aqueous solution of $0.02 \, \mathrm{M} \, {MgSO}_4$ electrolysed by passing a current of $9.65 \mathrm{~A}$ for 30 min. Mass of product obtained at cathode is

The standard cell potential for the cell is : $\mathrm{Zn}\left| {\mathrm{Z}{\mathrm{n}^{2 + }}\left( {1M} \right)} \right|\left| {\mathrm{C}{\mathrm{u}^{2 + }}\left( {1M} \right)} \right|\mathrm{Cu}$
$\left[ {{E^ \circ }{\kern 1pt} {\kern 1pt}{\rm{for {\kern 1pt} {\kern 1pt}Z}}{\mathrm{n}^{2 + }}/\mathrm{Zn} = - 0.76;{E^ \circ }{\kern 1pt} {\kern 1pt}{\rm{for {\kern 1pt} {\kern 1pt}C}}{\mathrm{u}^{2 + }}/\mathrm{Cu} = + 0.34} \right]$

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

$Zn$ amalgam is prepared by electrolysis of aqueous $ZnCl_2$ using $Hg$ cathode $(9 \mathrm{gm})$. How much current is to be passed through $ZnCl_2$ solution for 1000 seconds to prepare a $Zn$ Amalgam with $25 \% Zn$ by wt. $(Zn=65.4)$

On electrolysis of acidified water, if volume of hydrogen liberated is $5.6 \mathrm{~cm}^3$, then the volume of oxygen liberated equal to:

The potential of Hydrogen electrode $\left( {{P_{{H_2}}} = 1\mathrm{ atm },\mathrm{ }\left[ {{H^ + }} \right] = O.1M} \right)$ at ${25^\mathrm{o}}C$ will be

If the pressure of $\mathrm{H}_2(\mathrm{g})$ is increased from $1 \mathrm{~atm}$ to $100 \mathrm{~atm}$ keeping $\left[\mathrm{H}^{+}\right]$ constant at $1 \mathrm{M}$, the change in reduction potential of hydrogen half cell at $25^{\circ} \mathrm{C}$ will be:

By passage of 1F of electricity, through 1L of 1M solution
of an electrolyte which is not obtained

Passage of three faraday of charge through aqueous solution of $\mathrm{AgN}{\mathrm{O}_3},\mathrm{CuS}{\mathrm{O}_4},\mathrm{Al}{\left( {\mathrm{N}{\mathrm{O}_3}} \right)_3}$ and NaCl will deposit metals at the cathode in the molar ratio of:

Tell which of the following statements accurately describes the effect of adding $\mathrm{CN}^{-}$ to the cathode of a cell with a cell reaction:

$\mathrm{Cd}+2 \mathrm{Ag}^{+} \rightarrow 2 \mathrm{Ag}+\mathrm{Cd}^{2+}, E^{\circ}=1.2 \mathrm{~V}$

Cathode used in Leclanche cell is

Passage of electricity through dil ${H}_2 {SO}_4$ for 1 hour liberates a total of $224\, \mathrm{ml}$ of ${H}_2$ at S.T.P. The magnitude of current would be :-

Assertion: Molar conductivity of $\mathrm{CH}_3 \mathrm{COOH}$ increases with dilution.

Reason: The graph between $\lambda \mathrm{m} \mathrm{v} / \mathrm{s}(\mathrm{C})^{1 / 2}$ is a straight line for $\mathrm{CH}_3 \mathrm{COOH}$.

The conductivity of 0.1 (M) $\mathrm{NaOH}$ solution is 0.0221 $\mathrm{ohm}^{-1} \mathrm{~cm}^{-1}$. When an equal volume of 0.1 (M) $\mathrm{HCl}$ solution is added, the conductivity decreases to 0.0056 $\mathrm{ohm}^{-1} \mathrm{~cm}^{-1}$.
A further addition of $\mathrm{HCl}$ solution, the volume of which is equal to that of the first portion added, the conductivity increases to $0.017 \mathrm{ohm}^{-1} \mathrm{~cm}^{-1}$. What is the molar conductance at infinite dilution of $\mathrm{H}_2 \mathrm{O}$ in ohm ${ }^{-1}$ $\mathrm{cm}^2 \mathrm{~mol}^{-1}$ in nearest possible integers ?

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

Statement I: A metal having negative reduction
potential when dipped in the solution of its own
ions has a tendency to pass into the solution.

Statement II: Metals having negative reduction
potential have large hydration energy.