Redox Reactions and Electrochemistry — JEE Main PYQs

The equation that is incorrect is

For an electrochemical cell $\mathrm{Sn}(\mathrm{s})\left|{\mathrm{Sn}}^{2+}(\mathrm{aq},1\mathrm{M})\right|\left|{\mathrm{Pb}}^{2+}(\mathrm{aq},1\mathrm{M})\right|\mathrm{Pb}(\mathrm{s})$ the ratio $\frac{\left[{\mathrm{Sn}}^{2+}\right]}{\left[{\mathrm{Pb}}^{2+}\right]}$ when t …

Amongst the following, the form of water with the lowest ionic conductance at 298 K is :

The compound that cannot act both as oxidising and reducing agent is:

108 g of silver (molar mass $108$ $\mathrm{g}$ ${\mathrm{mol}}^{-1}$) is deposited at cathode from ${\mathrm{AgNO}}_3(\mathrm{aq})$ solution by a certain quantity of electricity. The volume (in L) of oxygen gas produced at 273 K and 1 bar pressure from water by the same quantity of …

The volume, in mL , of $0.02\mathrm{M}{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ solution required to react with 0.288 g of ferrous oxalate in acidic medium is ____ . (Molar mass of $\mathrm{Fe}=56{\mathrm{mol}}^{-1}$ )

Let ${\mathrm{C}}_{\mathrm{NaCl}}$ and ${\mathrm{C}}_{{\mathrm{BaSO}}_4}$ be the conductances (in S ) measured for saturated aqueous solution of NaCl and ${\mathrm{BaSO}}_4$, respectively, at a temperature T .

Which of the following is false?

The photoelectric current from Na (work function, ${\mathrm{w}}_0=2.3\mathrm{eV}$ ) is stopped by the output voltage of the cell …

An acidic solution of dichromate is electrolyzed for 8 minutes using 2 A current. As per the following equation ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}+14{\mathrm{H}}^{+}+6{\mathrm{e}}^{-}\to 2{\mathrm{Cr}}^{3+}+7{\mathrm{H}}_2\mathrm{O}$. The amount of ${\mathrm{Cr}}^{3+}$ ob …

For the given cell;
Cu(s)|Cu²⁺(C₁ M) || Cu²⁺(C₂ M)|Cu(s)
Change in Gibbs energy (ΔG) is negative, if

An oxidation - reduction in which 3 electrons are transferred has a $\Delta {\mathrm{G}}^0$ of $17.37\mathrm{kJ}{\mathrm{mol}}^{-1}$ at $25^{\circ }\mathrm{C}$. The value of ${\mathrm{E}}_{\text{cell }}^0$ (in V is ____ $\times 10^{-2}$) …

Potassium chlorate is prepared by the electrolysis of KCl in basic solution
$6{\mathrm{HO}}^{-}+{\mathrm{Cl}}^{-}\to {\mathrm{ClO}}_3^{-}+3{\mathrm{H}}_2\mathrm{O}+6{\mathrm{e}}^{-}$
If only $60\%$ of the current is utilized in the reaction, the time (rounded to the n …

On heating, lead (II) nitrate gives a brown gas (A). The gas (A) on cooling changes to a colourless solid/liquid (B). (B) on heating with NO changes to a blue solid (C). The oxidation number of nitrogen in solid (C) is:

Identify the incorrect statement from the options below for the above cell:

At 20.0 mL solution containing 0.2 g impure ${\mathrm{H}}_2{\mathrm{O}}_2$ reacts completely with 0.316 g of ${\mathrm{KMnO}}_4$ in acid solution. The purity of ${\mathrm{H}}_2{\mathrm{O}}_2$ (in %) is ____.
(mol. wt. of ${\mathrm{H}}_2{\mathrm{O}}_2=34$; mol. wt. of …

250 mL of a waste solution obtained from the workshop of a goldsmith contains 0.1 M ${\mathrm{AgNO}}_3$ and 0.1 M AuCl . The solution was electrolyzed at 2 V by passing a current of 1 A for 15 minutes. The metal/metals electrodeposited will be: …

Consider the following equations :
$2{\mathrm{Fe}}^{2+}+{\mathrm{H}}_2{\mathrm{O}}_2\to x\mathrm{A}+yB$ (in basic medium)
(in acidic medium) …

Given that ${\mathrm{E}}_{{\mathrm{O}}_2/{\mathrm{H}}_2\mathrm{O}}^0=+1.23\mathrm{V}$; ${\mathrm{E}}_{{\mathrm{S}}_2{\mathrm{O}}_8^{2-}/{\mathrm{SO}}_4^{2-}}^0=2.05\mathrm{V}$; ${\mathrm{E}}_{{\mathrm{Br}}_2/{\mathrm{Br}}^{-}}^0=+1.09\mathrm{V}$; …

In order to oxidize a mixture of one mole of each of ${\mathrm{FeC}}_2{\mathrm{O}}_4,{\mathrm{Fe}}_2{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3,{\mathrm{FeSO}}_4$ and ${\mathrm{Fe}}_2{\left({\mathrm{SO}}_4\right)}_3$ in acidic medium, the number of moles of …

Calculate the standard cell potential (in V ) of the cell in which following reaction takes place:
${\mathrm{Fe}}^2+(\mathrm{aq})+{\mathrm{Ag}}^{+}(\mathrm{aq})\to {\mathrm{Fe}}^{3+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s})$
Given that: …

The correct order of the oxidation states of nitrogen in $\mathrm{NO},{\mathrm{N}}_2\mathrm{O},{\mathrm{NO}}_2$ and ${\mathrm{N}}_2{\mathrm{O}}_3$ is:

The standard Gibbs energy for the given cell reaction in $\mathrm{kJ}{\mathrm{mol}}^{-1}$ at 298 K is:
$\mathrm{Zn}(\mathrm{s})+{\mathrm{Cu}}^{2+}(\mathrm{aq})⟶{\mathrm{Zn}}^{2+}(\mathrm{aq})+\mathrm{Cu}(\mathrm{s}),{\mathrm{E}}^{\circ }=2\mathrm{V}$ at 298 K
[Faraday' …

Consider the following …

Given the equilibrium constant:
${\mathrm{K}}_{\mathrm{C}}$ of the reaction:
$\mathrm{Cu}(\mathrm{s})+2\mathrm{Ag}+(\mathrm{aq})\to {\mathrm{Cu}}^2+(\mathrm{aq})+2\mathrm{Ag}(\mathrm{s})$ is …

An example of a disproportionation reaction is :

Given :
${\mathrm{Co}}^{3+}{\mathrm{e}}^{-}⟶{\mathrm{Co}}^{2+};{\mathrm{E}}^{\circ }=1.81\mathrm{V}$
${\mathrm{Pb}}^4+2{\mathrm{e}}^{-}⟶{\mathrm{Pb}}^{2+};{\mathrm{E}}^{\circ }=+1.67\mathrm{V}$ …

Which one of the following graphs between molar conductivity $\left({\Lambda }_m\right)$ versus $\sqrt{\mathrm{C}}$ is correct?

For the cell $\mathrm{Zn}(\mathrm{s})\left|{\mathrm{Zn}}^{2+}(\mathrm{aq})\right|\left|{\mathrm{M}}^{\mathrm{x}}+(\mathrm{aq})\right|\mathrm{M}(\mathrm{s})$, different half cells and their standard electrode potentials are given below:

| …

The standard electrode potential $E^{\circ }$ and its temperature coefficient $\left(\frac{d{E}^{\circ }}{dT}\right)$ for a cell are 2 V and $-5\times 10^{-4}$ VK${}^{-1}$ at 300 K respectively. The cell reaction is:

Standard reacti …

Iodine reacts with concentrated ${\mathrm{HNO}}_3$ to yield along with other products. The oxidation state of iodine in Y is

${\wedge }_{\mathrm{m}}^{\circ }$ for $\mathrm{NaCl}$, $\mathrm{HCl}$ and NaA are $126.4,425.9$ and $100.5\mathrm{S}{\mathrm{cm}}^2{\mathrm{mol}}^{-1}$, respectively. If the conductivity of 0.001 M HA is $5\times 10^{-5}{\mathrm{Scm}}^{-1}$, degree of dissociation of HA is :

A solution of $\mathrm{Ni}{\left({\mathrm{NO}}_3\right)}_2$ is electrolysed between platinum electrodes using 0.1 Faraday electricity. How many mole of Ni will be deposited at the cathode?

If the standard electrode potential for a cell is 2 V at 300 K , the equilibrium constant $(\mathrm{K})$ for the reaction
$\mathrm{Zn}(\mathrm{s})+{\mathrm{Cu}}^{2+}(\mathrm{aq})\rightleftharpoons {\mathrm{Zn}}^{2+}(\mathrm{aq})+\mathrm{Cu}(\mathrm{s})$
At 300 K is approximately …

The anodic half-cell of lead-acid battery is recharged using electricity of 0.05 Faraday. The amount of ${\mathrm{PbSO}}_4$ electrolyzed in g during the process is:
(Molar mass of ${\mathrm{PbSO}}_4=303\mathrm{g}{\mathrm{mol}}^{-1}$)

Consider the statements S1 and S2:
S1: Conductivity always increases with decrease in the concentration of electrolyte.
S2: Molar conductivity always increases with decrease in the concentration of electrolyte.
The correct option among the following is:

How long (approximate) should water be electrolysed by passing through 100 amperes current so that the oxygen released can completely burn 27.66 g of diborane ?
(Atomic weight of $\mathrm{B}=10.8\mathrm{u}$)

Which of the following reactions is an example of a redox reaction?

Given
${\mathrm{E}}_{{\mathrm{Cl}}_2/{\mathrm{Cl}}^{-}}^{\circ }=1.36\mathrm{V},{\mathrm{E}}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^{\circ }=-0.74\mathrm{V}$ …

The pair in which phosphorous atoms have a formal oxidation state of +3 is:

Galvanization is applying a coating of:

Two Faraday of electricity is passed through a solution of ${\mathrm{CuSO}}_4$. The mass of copper deposited at the cathode is: (at. mass of $\mathrm{Cu}=63.5\mathrm{amu}$)

The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is:

Resistance of 0.2 M solution of an electrolyte is $50\Omega$. The specific conductance of the solution is $1.4\mathrm{S}{\mathrm{m}}^{-1}$. The resistance of 0.5 M solution of the same electrolyte is $280\Omega$. The molar conductivity of 0.5 M solution of the electrolyte in …

The equivalent conductance of NaCl at concentration C and at infinite dilution are ${\lambda }_{\mathrm{C}}$ and ${\lambda }_{\infty }$, respectively. The correct relationship between ${\lambda }_{\mathrm{C}}$ and ${\lambda }_{\infty }$ is given as:
(where the constant B is positive)

Given below are the half-cell reactions:
${\mathrm{Mn}}^{2+}+2{\mathrm{e}}^{-}⟶\mathrm{Mn};{\mathrm{E}}^0=-1.18\mathrm{V}$
$2\left({\mathrm{Mn}}^{3+}+{\mathrm{e}}^{-}⟶{\mathrm{Mn}}^{2+}\right);{\mathrm{E}}^0=+1.51\mathrm{V}$
The …

Given
${\mathrm{E}}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^0=-0.74\mathrm{V};{\mathrm{E}}_{{\mathrm{MnO}}_4^{-}/{\mathrm{Mn}}^{2+}}^0=1.51\mathrm{V}$ …

Consider the following reaction:

The values of $\mathrm{x},\mathrm{y}$ and z in the reaction are, res …

The standard reduction potentials for ${\mathrm{Zn}}^{2+}/\mathrm{Zn},{\mathrm{Ni}}^{2+}/\mathrm{Ni}$, and ${\mathrm{Fe}}^{2+}/\mathrm{Fe}$ are $-0.76,-0.23$ and -0.44 V respectively. The reaction $\mathrm{X}+{\mathrm{Y}}^{2+}\to {\mathrm{X}}^{2+}+\mathrm{Y}$ will be sponta …

The reduction potential of hydrogen half cell will be negative if :

The Gibbs energy for the decomposition of ${\mathrm{Al}}_2{\mathrm{O}}_3$ at $500^{\circ }\mathrm{C}$ is as follows: …