Chemistry 12 Chapter 4 Exemplar Solutions Chemical Kinetics Part 2

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Question 8:

A graph of volume of hydrogen released vs time for the reaction between zinc and is given in Fig. 4.2. On the basis of this mark the correct option.

Volume of hydrogen

Volume of Hydrogen

Fig. 4.2

(i) Average rate upto is

(ii) Average rate upto seconds is

(iii) Average rate upto seconds is

(iv) Average rate upto seconds is

Answer: (iii)

Question 9:

Which of the following statements is not correct about order of a reaction.

(i) The order of a reaction can be a fractional number.

(ii) Order of a reaction is experimentally determined quantity.

(iii) The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.

(iv) The order of a reaction is the sum of the powers of molar concentration of the reactants in the rate law expression.

Answer: (iii)

Question 10:

Consider the graph given in Fig. 4.2. Which of the following options does not show instantaneous rate of reaction at second?

(i)

(ii)

(iii) )

(iv) )

Answer: (ii)

Question 11:

Which of the following statements is correct?

(i) The rate of a reaction decreases with passage of time as the concentration of reactants dereases.

(ii) The rate of a reaction is same at any time during the reaction.

(iii) The rate of a reaction is independent of temperature change.

(iv) The rate of a reaction decreases with increase in concentration of reactant(s).

Answer: (i)

Question 12:

Which of the following expressions is correct for the rate of reaction given below?

(i)

(ii)

(iii)

(iv)

Answer: (iii)

Question 13:

Which of the following graphs represents exothermic reaction?

(a)

Represents exothermic reaction

Represents Exothermic Reaction

(b)

Represents exothermic reaction

Represents Exothermic Reaction

(c)

Represents exothermic reaction

Represents Exothermic Reaction

(i) (a) only

(ii) (b) only

(iii) (c) only

(iv) (a) and (b)

Answer: (i)

Question 14:

Rate law for the reaction is found to be

Concentration of reactant ‘B’ is doubled, keeping the concentration of ‘A’ constant, the value of rate constant will be______.

(i) The same

(ii) Doubled

(iii) Quadrupled

(iv) Halved

Answer: (ii)

Question 15:

Which of the following statements is incorrect about the collision theory of chemical reaction?

(i) It considers reacting molecules or atoms to be hard spheres and ignores their structural features.

(ii) Number of effective collisions determines the rate of reaction.

(iii) Collision of atoms or molecules possessing sufficient threshold energy results into the product formation.

(iv) Molecules should collide with sufficient threshold energy and proper orientation for the collision to be effective.

Answer: (iii)

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