Ncert Solutions Chemistry Class 12th

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (iv)

The cell constant is described as the ratio of the length of the object and the area of cross-section. It can be written as follow

G= $\frac{\mathrm{l}}{\mathrm{A}}$

As l and A remains constant for an object it can be inferred that the cell constant for a conductivity cell remains constant for a cell.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options: A and D 

Elementary reaction: It is a reaction that occurs in a single step.

Here we must understand about the Order and Molecularity.

Molecularity of a reaction = number of reacting species (collide to bring a chemical reaction).

Discussing about the Order, Rate law is used in Order and how do we equate shall be seen in the next step

rate = k [A] ^α [B] ^β

For a balanced chemical equation of an elementary reaction Order and Molecularity is same and can never be 0. 

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct Option: (iii)

 Ans: Given: One mole of aluminium

Calculate the number of electrons required to convert Al₂O₃ to Al

It is the charge required to obtain one mole of aluminium from Al₂O₃

The dissociation of aluminium oxide is as follows;

Al₂O₃→2Al³⁺+3O²⁻

Al³⁺+3e⁻→Al

Therefore 3Fcharge is required to obtain one mole of aluminum from Al₂O_3.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (i)

According to the given table, has the most negative value among the given species. So

Cr³⁺ is the most stable oxidized species.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Correct options : A, C and D.

Rate law = Experimental rate of the reaction

Suppose aA + bB→cC + dD

Then rate = k [A] ^α [B] ^β

Here instead of using complex reaction we use elementary reaction which gets solved in one step

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (iv)

is the highest positive value among the given species. So Mn²⁺ is the most stable ion in its reduced form.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (iii)

According to the electrochemical series, the lower the reduction potential higher is the reducing power.

Therefore, the order of reducing power is Mn²⁺ < Cl < Cr³⁺ < Cr

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (iii)

According to the electrochemical series higher the positive value of standard reduction potential of metal ion, the higher is the oxidizing power

Therefore, MnO₄⁻ is the strongest oxidizing agent.

This is a Short Answer Type Question as classified in NCERT Exemplar

Incorrect order results from a balanced chemical equation. KClO₃ + 6FeSO₄ + 3H₂SO₄→KCl + 3H₂O + 3Fe₂ (SO₄)₃

This reaction is complex and occurs in several steps. The order is determined by the slowest in the reactions

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (ii)

According to the electrochemical series and standard reduction potential of metal, the higher the negative value of standard reduction potential stronger will be the reducing agent

In the given options, the standard reduction potential of chromium has the highest value so it is the strongest reducing agent.