Q29 of 37 Page 109

In the following questions a statement of assertion (A) followed by a statement of reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): In the reaction between potassium permanganate and potassium iodide, permanganate ions act as oxidising agent.


Reason (R): Oxidation state of manganese changes from +2 to +7 during the reaction.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) Both A and R are false.


Option (iii) A is true but R is false.


The above shows the reaction is a redox reaction, where Mn undergoes reduction from +7 to +4 and Iodine undergoes oxidation from -1 to 0. The maximum oxidation state that Mn can reach according to electronic configuration is +7. Thus as it cannot undergo oxidation it acts as oxidising agent and itself undergoes reduction, whereas Iodine undergoes oxidation from -1 to 0.


Oxidation state of Mn changes from +7 to +4 an thus (B) is false.


More from this chapter

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27

Match the items in Column I with relevant items in Column II.

28

In the following questions a statement of assertion (A) followed by a statement of reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): Among halogens fluorine is the best oxidant. Reason (R): Fluorine is the most electronegative atom.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) Both A and R are false.


30

In the following questions a statement of assertion (A) followed by a statement of reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.


Reason (R) : The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in O2 and –2 oxidation state in H2O.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) Both A and R are false.


31

In the following questions a statement of assertion (A) followed by a statement of reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A) : Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.


Reason (R) : In the representation E° Fe3+/fe2+and E°cu2+/cu , Fe3+ / Fe2+ and Cu2+ are redox couples.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) Both A and R are false