Class 12th

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, iii)

Electrolysis of copper sulfate solution is as follows

CuSO₄ ? Cu²⁺ + SO₄²⁻

H₂O? H⁺ + OH⁻

At the cathode, the reaction goes this way,

Cu²⁺ + 2e− → Cu; E? _Cell = 0.34V

H₂O⁻ → $\frac{1}{2}$ H₂ E? _Cell = 0.00V

At the anode, the reaction goes this way,

2SO₄^2- + 2e−→S₂O₈²⁻ E? _Cell =1.96V

2H₂O→O₂ + 4H⁺ + 4e⁻ E? _Cell =1.23V

The reaction will lower the value of E? _Cell is preferred at anode so the second reaction is feasible.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, iii)

 Kohlrausch law of states that limiting molar conductivity of any salt species is equal to the sum of the limiting molar conductivity of cations and anions of the electrolyte

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and C

The Maxwell Boltzmann distribution, often known as the Gibbs distribution, is a measure that expresses the likelihood of a system being in each state as a function of the energy of that state.

Look at the graph.

T₂ > T₁

The fraction of molecules falls as the temperature rises because the area under the curve shrinks.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, ii)

Conductivity is due to the movement of ions in the solution. The conductivity of ions depends on the following factors:

(i) nature of electrolyte added

(ii) size of ion produced

(iii) concentration of electrolyte

(iv) nature of the solvent

(v) temperature

Distance between electrodes does not affect the conductivity of an electrolytic solution.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (ii, iii)

At equilibrium, ?G $°$  = -2.303 RT ${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

-nFE $°$  = -2.303 RT ${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

E $°$ = $\frac{2.303\mathrm{}\mathrm{R}\mathrm{T}}{\mathrm{n}\mathrm{F}}{\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

For Daniel cell, n=2

E $°$ = $\frac{2.303\mathrm{}\mathrm{R}\mathrm{T}}{2\mathrm{F}}{\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

At equilibrium, E $°$ = 1.1V

1.1V = $\frac{2.303\mathrm{}\mathrm{R}\mathrm{T}}{2\mathrm{F}}{\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}=\mathrm{}\frac{2.2}{0.059}$

(i) Since ${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}=\mathrm{}\frac{2.2}{0.059}$  this option is incorrect

(ii) As derived 1.1V = $\frac{2.303\mathrm{}\mathrm{R}\mathrm{T}}{2\mathrm{F}}{\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}$

(iii) As derived _{${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}=\mathrm{}\frac{2.2}{0.059}$} so this option is correct

(iv) As ${\mathrm{l}\mathrm{o}\mathrm{g}\mathrm{K}}_{\mathrm{c}}=\mathrm{}\frac{2.2}{0.059}$  _,so this option is incorrect

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D

Activation Energy is the amount of energy released when reactant molecules collide and form an activated complex. When energy is released, the complex decomposes into a product.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, iii)

In the electrolysis of sulphuric acid, the following reactions occur

2SO₄²⁻ (aq)→S₂O₈²⁻ (aq) + 2e⁻ E? _Cell =1.96V

2H₂O (l)→O₂ (g)+4H⁺ (aq) + 4e⁻ E? _Cell =1.23V

The reaction will lower the value of E? _Cell is preferred at anode so the second reaction is feasible.

H⁺ + e⁻ → $\frac{1}{2}$ H₂ E? _Cell = 0.00V

At the cathode, reduction of water occurs. Therefore, in dilute sulphuric acid solution, hydrogen will be reduced at the cathode.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A, C and D

The pressure in this reaction is extremely high, and it becomes independent of the ammonia concentration. The metal surface becomes saturated with gas molecules when the rate of reaction=Rate constant. The rate of a zero-order reaction is independent of the concentration of reactants in the reaction.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (ii, iv)

The lesser the E? value of the redox couple higher is the reducing power

For Cu²⁺ + 2e⁻→Cu; E? =0.34V

For 2H⁺ + 2e⁻→H₂ E? =0.00V

Since the second redox couple has less standard reduction potential than the first so it can be concluded that the redox couple is a stronger oxidizing agent than H⁺/H₂ and copper cannot displace H₂ from acid.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D

A complex reaction is one that does not happen in a single step.

The total number of molecules involved in the slowest step of the reaction determines the overall reaction rate.