Redox Reactions and Electrochemistry — JEE Advanced PYQs

At 300 K, the molar conductivities of the aqueous solutions of three salts at two different concentrations are given below:
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In an electrochemical cell, dichromate ions in aqueous acidic medium are reduced to ${\mathrm{Cr}}^{3+}$. The current (in amperes) that flows through the cell for 48.25 minutes to produce 1 mole of ${\mathrm{Cr}}^{3+}$ is ____.

Use: 1 Faraday $=96500\mathrm{C}{\mathrm{mol}}^{-1}$

An electrochemical cell is fueled by the combustion of butane at 1 bar and 298 K. Its cell potential is $\frac{\mathbf{X}}{\mathbf{F}}\times 10^3$ volts, where $\mathbf{F}$ is the Faraday constant. The value of $\mathbf{X}$ is ____.

Use : Standard Gibbs energi …

In a conductometric titration, small volume of titrant of higher concentration is added stepwise to a larger volume of titrate of much lower concentration, and the conductance is measured after each addition.
The limiting ionic conductivity (${\Lambda }_0$) values (in …

An aqueous solution of hydrazine $\left({\mathrm{N}}_2{\mathrm{H}}_4\right)$ is electrochemically oxidized by ${\mathrm{O}}_2$, thereby releasing chemical energy in the form of electrical energy. One of the products generated from the electrochemical reaction is …

${\mathrm{H}}_2\mathrm{S}$ (5 moles) reacts completely with acidified aqueous potassium permanganate solution. In this reaction, the number of moles of water produced is $\mathbf{x}$, and the number of moles of electrons involved is $\mathbf{y}$. The value of …

Consider the following molecules : ${\mathrm{Br}}_3{\mathrm{O}}_8,{\mathrm{F}}_2\mathrm{O},{\mathrm{H}}_2{\mathrm{S}}_4{\mathrm{O}}_6,{\mathrm{H}}_2{\mathrm{S}}_5{\mathrm{O}}_6$, and ${\mathrm{C}}_3{\mathrm{O}}_2$.
Count the number of atoms existing in their zero …

Plotting $1/{\Lambda }_{\mathrm{m}}$ against $\mathrm{c}{\Lambda }_{\mathrm{m}}$ for aqueous solutions of a monobasic weak acid (HX) resulted in a straight line with y-axis intercept of P and slope of S. The ratio P/S is

[${\Lambda }_{\mathrm{m}}=$ molar conductivity …

The reduction potential ( $E^0$, in V ) of ${\mathrm{MnO}}_4^{-}(\mathrm{aq})/\mathrm{Mn}(\mathrm{s})$ is ____. …

Consider the strong electrolytes ${\mathrm{Z}}_{\mathrm{m}}{\mathrm{X}}_{\mathrm{n}}$, ${\mathrm{U}}_{\mathrm{m}}{\mathrm{Y}}_{\mathrm{p}}$ and ${\mathrm{V}}_{\mathrm{m}}{\mathrm{X}}_{\mathrm{n}}$. Limiting molar conductivity ( ${\Lambda }^o$ ) of …

Some standard electrode potentials at 298 K are given below:
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At 298 K, the limiting molar conductivity of a weak monobasic acid is $4\times 10^2\mathrm{S}{\mathrm{cm}}^2{\mathrm{mol}}^{-1}$. At 298 K, for an aqueous solution of the acid the degree of dissociation of $\mathbf{\alpha }$ and the molar conductivity is …

At 298 K, the limiting molar conductivity of a weak monobasic acid is $4\times 10^2\mathrm{S}{\mathrm{cm}}^2{\mathrm{mol}}^{-1}$. At 298 K, for an aqueous solution of the acid the degree of dissociation of $\mathbf{\alpha }$ and the molar conductivity is …

In the chemical reaction between stoichiometric quantities of ${\mathrm{KMnO}}_4$ and KI in weakly basic solution, what is the number of moles of ${\mathrm{I}}_2$ released for 4 moles of ${\mathrm{KMnO}}_4$ consumed?

Consider a 70% efficient hydrogen-oxygen fuel cell working under standard conditions at 1 bar and 298 K. Its cell reaction is

The work derived from the cell on the …

For the electrochemical cell,

the standard emf of the cell is 2.70 V at 300K. When the concentration of …

To measure the quantity of ${\mathrm{MnCl}}_2$ dissolved in an aqueous solution, it was completely converted to ${\mathrm{KMnO}}_4$ using the reaction, …

The surface of copper gets tarnished by the formation of copper oxide. ${\mathrm{N}}_2$ gas was passed to prevent the oxide formation during heating of copper at 1250 K. However, the ${\mathrm{N}}_2$ gas contains 1 mole % of water vapour as impurity. The water vapour oxidises cop …

Consider an electrochemical cell: $\mathrm{A}(\mathrm{s})|{\mathrm{A}}^{\mathrm{n}+}(\mathrm{aq},2\mathrm{M})||{\mathrm{B}}^{2\mathrm{n}+}(\mathrm{aq},1\mathrm{M})|\mathrm{B}(\mathrm{s})$. The value of $\Delta H^{\ominus }$ for the cell reaction is twice that of $\Delta G^{\ominus }$ …

For the following cell,

when the concentration of ${\mathrm{Zn}}^{2+}$ is 10 times the concentration of ${\mathrm{Cu}}^{2+}$, the expression for $\Delta G$ (in …

Which of the following combination will produce ${\mathrm{H}}_2$ gas?

The order of the oxidation state of the phosphorus atom in ${\mathrm{H}}_3{\mathrm{PO}}_2,{\mathrm{H}}_3{\mathrm{PO}}_4,{\mathrm{H}}_3{\mathrm{PO}}_3$, and ${\mathrm{H}}_4{\mathrm{P}}_2{\mathrm{O}}_6$ is

The conductance of a 0.0015 M aqueous solution of a weak monobasic acid was determined by using a conductivity cell consisting of platinized Pt electrodes. The distance between the electrodes is 120 cm with an area of cross section of $1{\mathrm{cm}}^2$. The conductance of this …

In neutral or faintly alkaline solution, 8 moles of permanganate anion quantitatively oxidize thiosulphate anions to produce $\mathbf{X}$ moles of a sulphur containing product. The magnitude of $\mathbf{X}$ is

For the following electrochemical cell at 298 K, …

All the energy released from the reaction $\mathbf{X}\to \mathbf{Y},{\Delta }_r{G}^0=-193\mathrm{kJ}{\mathrm{mol}}^{-1}$ is used for oxidizing ${\mathbf{M}}^{+}$as ${\mathbf{M}}^{+}\to {\mathbf{M}}^{3+}+2{\mathrm{e}}^{-},E^0=-0.25V$.
Under standard conditi …

Copper is purified by electrolytic refining of blister copper. The correct statement(s) about this process is (are)

The molar conductivity of a solution of a weak acid HX (0.01 M) is 10 times smaller than the molar conductivity of a solution of a weak acid HY (0.10 M). If λ⁰ₓ₋ ≈ λ⁰ᵧ₋, the difference in their pKₐ values, pKₐ(HX) - pKₐ(HY), is (consider degree of ionization of both acids to be < …

In dilute aqueous H₂SO₄, the complex diaquodioxalatoferrate(II) is oxidized by MnO₄⁻. For this reaction, the ratio of the rate of change of [H⁺] to the rate of change of [MnO₄⁻] is

In a galvanic cell, the salt bridge

For the reaction:

The correct statement(s) in the balanced equation is/are:

Consider the following list of reagents:

Acidified ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$, alkaline ${\mathrm{KMnO}}_4,{\mathrm{CuSO}}_4,{\mathrm{H}}_2{\mathrm{O}}_2,{\mathrm{Cl}}_2,{\mathrm{O}}_3,{\mathrm{FeCl}}_3,{\mathrm{HNO}}_3$ and …

The unbalanced chemical reactions given in List I show missing reagent or condition (?) which are provided in List II. Match List I with List II and select the correct answer using the code given below the lists:
| P. | …

The standard reduction potential data at 25 °C is given below. …

An aqueous solution of $\mathbf{X}$ is added slowly to an aqueous solution of $\mathbf{Y}$ as shown in List I. The variation in conductivity of these reactions is given in List II. Match List I with List II and select the correct answer using the code given below the lists: …

The electrochemical cell shown below is a concentration cell.
$\mathrm{M}\mid {\mathrm{M}}^{2+}$ (saturated solution of a sparingly soluble salt, ${\mathrm{MX}}_2$ ) \| ${\mathrm{M}}^{2+}\left(0.001\mathrm{mol}{\mathrm{dm}}^{-3}\right)\mid \mathrm{M}$
The emf of the cell dep …

The electrochemical cell shown below is a concentration cell.
$\mathrm{M}\mid {\mathrm{M}}^{2+}$ (saturated solution of a sparingly soluble salt, ${\mathrm{MX}}_2$ ) \| ${\mathrm{M}}^{2+}\left(0.001\mathrm{mol}{\mathrm{dm}}^{-3}\right)\mid \mathrm{M}$
The emf of the cell dep …

Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen?

Consider the following cell reaction:
$2{\mathrm{Fe}}_{(\mathrm{s})}+{\mathrm{O}}_{2(\mathrm{g})}+4{\mathrm{H}}_{(\mathrm{aq})}^{+}\to 2{\mathrm{Fe}}_{(\mathrm{aq})}^{2+}+2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}{\mathrm{E}}^{\circ }=1.67\mathrm{V}$
At …

${\mathrm{AgNO}}_3$ (aq.) was added to an aqueous KCl solution gradually and the conductivity of the solution was measured. The plot of conductance ( $\Lambda$ ) versus the volume of ${\mathrm{AgNO}}_3$ is

The difference in the oxidation numbers of the two types of sulphur atoms in ${\mathrm{Na}}_2{\mathrm{S}}_4{\mathrm{O}}_6$ is

Reaction of ${\mathrm{Br}}_2$ with ${\mathrm{Na}}_2{\mathrm{CO}}_3$ in aqueous solution gives sodium bromide and sodium bromate with evolution of ${\mathrm{CO}}_2$ gas. The number of sodium bromide molecules involved in the balanced chemical equation is

The concentration of potassium ions inside a biological cell is at least twenty times higher than the outside. The resulting potential difference across the cell is important in several processes such as transmission of nerve impulses and maintaining the ion balance. A simple mod …

The concentration of potassium ions inside a biological cell is at least twenty times higher than the outside. The resulting potential difference across the cell is important in several processes such as transmission of nerve impulses and maintaining the ion balance. A simple mod …

For the reduction of ${\mathrm{NO}}_3^{-}$ion in an aqueous solution, ${\mathrm{E}}^0$ is +0.96 V. Values of ${\mathrm{E}}^0$ for some metal ions are given below …

Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of ${\mathrm{H}}_2$ gas at the cathode is (1 Faraday = 96500 C mol⁻¹)

Match the reactions in Column I with nature of the reactions/type of the products in Column II. Indicate your answer by darkening the appropriate bubbles of the $4\times 4$ matrix given in the ORS.
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