Chemistry

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option C

Option (c) is the only one of the four assertions that is incorrect. In rate law expression, the order of reaction is equal to the sum of the power of concentration of the reactants.

xA + yB→zC

r = k (A)^x (B)^y 

Order x + y

The order of the reactions can also be a fraction. In a balanced chemical equation, the order of reaction may or may not be equal to the total of the stoichiometric coefficients of the reactants.

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option C

In the given graph V is the volume in the Y axis and time is in X axis

Zn + dil.HCl→ZnCl₂ + H₂↑

Average rate = 40s

Average rate of reaction = $\frac{\mathrm{C}\mathrm{h}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{e}\mathrm{}\mathrm{i}\mathrm{n}\mathrm{}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{c}\mathrm{e}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{}\mathrm{o}\mathrm{f}\mathrm{}{\mathrm{H}}_2}{\mathrm{C}\mathrm{h}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{e}\mathrm{}\mathrm{i}\mathrm{n}\mathrm{}\mathrm{t}\mathrm{i}\mathrm{m}\mathrm{e}}$

$\frac{\mathrm{F}\mathrm{i}\mathrm{n}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{c}\mathrm{e}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}-\mathrm{I}\mathrm{n}\mathrm{i}\mathrm{t}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{c}\mathrm{e}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}}{\mathrm{F}\mathrm{i}\mathrm{n}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{t}\mathrm{i}\mathrm{m}\mathrm{e}-\mathrm{}\mathrm{I}\mathrm{n}\mathrm{i}\mathrm{t}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{T}\mathrm{i}\mathrm{m}\mathrm{e}}$

Analyzing the graph line where time and volume intersect. 

$\frac{{\mathrm{V}}_3-0}{40-0}$

$\frac{{\mathrm{V}}_3}{40}$

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option D

k = Ae -    $\frac{\mathbf{}\mathbf{E}\mathbf{a}}{\mathbf{R}\mathbf{T}}$             

From this equation

Kα $\frac{1}{\mathrm{E}\mathrm{a}}$

When Activation energy Ea decreases, rate constant k

 increases.

Hence, Rate constant increases exponentially with decreasing activation energy and increasing temperature. 

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option A

Arrhenius equation Ae -   $\frac{\mathbf{}\mathbf{E}\mathbf{a}}{\mathbf{R}\mathbf{T}}$

K = rate constant

A= frequency factor

Ea= Activation Energy

R= gas constant

T= temperature

ln k = lnA - $\frac{\mathbf{E}\mathbf{a}}{\mathbf{R}\mathbf{T}}$

When the temperature rises, ln falls.

∴ ln kv/s $\frac{1}{\mathbf{T}}\mathrm{}$ , is a negative slope.

ln A is intercepted by k, and its magnitude decreases with time.

∴ Negative slope is obtained.

When compared to the other possibilities, T is increasing over time, which is incorrect.

ln k =  $\frac{-\mathbf{E}\mathbf{a}}{\mathbf{R}}$ $\frac{1}{\mathbf{T}}\mathbf{}$  + lnA

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option B

Given:  

A (g) → B (g) + C (g) 

p_i= Initial pressure

(Time) t = 0

A (g) → B (g) + C (g) 

p_i        →0atm + 0atm

t, (p_i - x)atm

p_t = (p_i - x)atm + x + x = p_i + x

p_A = (p_i - x)

The value of x changes when it is substituted.

p_A = p_i - (p_t - p_i) = 2p_i - p_t

K =  $\frac{2.303}{\mathrm{t}}$ log $\frac{{\mathrm{p}}_{\mathrm{i}}}{2{\mathrm{p}}_{\mathrm{i}}-{\mathrm{p}}_{\mathrm{t}}}$

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option A

Activation Energy → The amount of energy required to overcome the obstacle and generate a product

The activation energy of a forward reaction can be seen in the [E_af = E₁ + E₂] (This is an endothermic reaction.

Therefore, [E_af > E_ab]   

The energy of the product is high, while the energy of the reactant is low.

The lower the energy, the more stable and positive the situation becomes.

Δ? = posistive

The NCERT Exemplar includes analytical, application-based, and reasoning-type questions. It goes beyond the NCERT textbooks and helps students apply theories like VSEPR, hybridization, and MOT. It helps students to prepare for various entrance exams like NEET and JEE by strengthening their conceptual clarity.

Hybridization predicts the geometry and bond angles in complex molecules and it helps in the understanding of how four equivalent bonds in methane (CH? )  can be formed from atoms like carbon. For observed molecular geometries, it explains the formation of the equivalent orbitals (like sp³, sp², sp).

In molecular shape prediction, VSEPR (Valence Shell Electron Pair Repulsion) theory is important because based on the repulsions between the electron pairs around the central atom, it helps in predicting the three-dimensional shape of molecules. The 3D shape influences the molecule's chemical and physical properties including reactivity, polarity, and intermolecular forces.

This is a assertion and reason answer type question as classified in NCERT Exemplar

Because m-nitrochlorobenzene is not a stable molecule, the -NO₂ group is a meta-directing group, and the reactions' products include nitro groups at the o- and p- positions.

Correct Answer: Option (iv)