Class 12th

This is a Matching Type Questions as classified in NCERT Exemplar

Ans: (i)The unit of  Λm is Scm²mol⁻¹

(ii) The unit of E_cell is m⁻¹

(iii) The unit of k is Scm⁻¹

(iv)The unit of  G∗ is m⁻¹

Hence, the answer is:

(i)-c ; (ii)-d ; (iii)-a ; (iv)-b

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D

The pace of a reaction that is directly proportional to the concentration of the reacting substance is known as a first order reaction. 

Y=mn

k = $\frac{2.303}{\mathrm{t}}\mathrm{}$ log  $\frac{\mathbf{ }\mathbf{a}}{\mathbf{a}-\mathbf{x}\mathbf{ }}$

t = $\frac{2.303}{\mathrm{k}}\mathrm{}$ log $\frac{\mathbf{ }\mathbf{a}}{\mathbf{a}-\mathbf{x}\mathbf{ }}$

x= a- $\frac{\mathbf{a}}{2}$

x= $\frac{\mathbf{a}}{2}$

t $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\mathbf{}$ _{= $\frac{2.303}{\mathrm{k}}\mathrm{}$} log $\frac{\mathbf{ }\mathbf{a}}{\mathbf{a}-\frac{\mathbf{a}}{2}\mathbf{ }}$   

$\frac{2.303}{\mathrm{k}}$ log2

= $\frac{0.693}{\mathrm{k}}$

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D

A Zero order reaction = [R] =  ( - k)t +  [R]₀

y = (m *  ) + c

x = t (time)

y =  [R]concentration

Slope (m) =  - k

Intercept (c) =  [R]₀

  $\frac{\left. [\mathbf{R}\right]\mathbf{ }-\mathbf{ }{\left. [\mathbf{R}\right]}_0}{\mathbf{t}}$ =  - k

$\frac{\left. [\mathbf{R}\right]\mathbf{ }-\mathbf{ }{\left. [\mathbf{R}\right]}_0}{\mathbf{t}}$ =  - kt^o

Rate ∝ t⁰

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (ii, iii)

In the given representation of the cell, the left side represents the oxidation half cell and the right side of the cell represents the reduction half cell

The electrode at which oxidation occurs is called anode and oxidation of magnesium occurs at anode so magnesium is the anode.

Similarly, the electrode at which the reduction occurs is called the cathode, and the reduction of copper occurs at the cathode.

The cell reaction is as follows

Mg + Cu²⁺→Mg²⁺+ Cu

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, iii)

The conductivity in an ionic solution is due to the ions in the solution. It depends on the following factors;

(a)Temperature: On an increase in temperature, the molar conductivity of ionic solutions increases.

(b)Concentration of Electrolytes: An increase in the concentration of electrolytes decreases the molar conductivity as the number of ions per unit volume decreases.

Therefore, options (i, iii) are correct

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: B, C and D

Catalysts reduce the activation energy of a process and give an alternate path by reducing or raising the activation energy between reactants and products, altering the reaction's enthalpy change. As a result, B, C, and D statements are the proper responses

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, ii)

Conductance is the reciprocal of resistance and conductivity is the reciprocal of resistivity. It can be written as follows

k = $\frac{1}{\mathbf{?}}$

R= $\mathbf{?}\mathbf{}\frac{1}{\mathbf{A}}$

$\mathbf{?}$ = $\frac{\mathbf{R}\mathbf{A}}{\mathbf{l}}$

k  = $\frac{1}{\frac{\mathbf{R}\mathbf{A}}{\mathbf{l}}}$

k = $\frac{1}{\mathbf{R}}\frac{\mathbf{l}}{\mathbf{A}}$

k = $\frac{1}{\mathbf{R}}$ G*

k = $\frac{{\mathbf{G}}^{\mathbf{*}}}{\mathbf{R}}$

G* is cell constant.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: Option (i, ii)

In the electrolysis process of CuSO₄ the following reactions occur at the half cell which is as follows:

At the cathode, the reaction goes this way,

Cu²⁺+2e⁻→Cu (s)

At the anode, the reaction goes this way,

Cu (s)→Cu²⁺+2e−

Here copper will be deposited at the cathode and copper will dissolve at the anode.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and B

Arrhenius equation k = Ae – $\frac{{\mathbf{E}}_{\mathbf{a}}}{\mathbf{R}\mathbf{T}}$

When the temperature rises, $\frac{{\mathbf{E}}_{\mathbf{a}}}{\mathbf{R}\mathbf{T}}$ value falls and – $\frac{{\mathbf{E}}_{\mathbf{a}}}{\mathbf{R}\mathbf{T}}$

As a result, e- $\frac{{\mathbf{E}}_{\mathbf{a}}}{\mathbf{R}\mathbf{T}}$  increases, and it is certain that k and  T increases as well. As a result, Option A is proven.

Catalyst increases the rate of reaction by lowering the activation energy. Thus option B is also correct. 

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D

According to the graph, the area under the cure must not vary as the temperature rises.T2 > T1

The energy level of T2 is higher than T1.