Chemistry Chapter 7 Entry Test MCQs
Topic 7
Rate of reaction and Rate Constant + Factors
1. The rate of reaction
a. Decreases as the reaction proceeds
b. Increases as the reaction proceeds
c. May decrease or increase as the reaction proceeds
d. Remains the same as the reaction proceeds
2. -d[N2O5]/dt represents
a. The rate of decomposition of N2O5
b. The rate of formation of N2O5
c. Amount of the reactant
d. Order of the reaction
3. Greater the concentration Of reactant
a. dx/dt will be moderate
b. Greater will be dx/dt
c. any of above
d. Lesser will be dx/dt
4. In rate expression the concentration of reactants is negative. It shows
a. The concentration of reactant decreases
b. The concentration of reactant does not change
c. The concentration of reactant increases
d. The concentration of product increases
5. The rate constant of a reaction depends on
a. Temperature
b. Extent of reaction
c. Initial conc. of the reactants
d. Time of reaction
6. The specific rate constant of a first order reaction depends on the
a. Time
b. Concentration of the reactant
c. Temperature
d. Concentration of the product
7. Unit of rate of reaction
a. sec–1
b. moldm–3 sec–1
c. mol–dm–3 sec+1
d. mol– dm+3 sec–1
8. The rate constant of a first order reaction, A → products, is 60 × 10-4 s-1. Its rate at [A] = 0.01 mol 1-1 would be
a. 60×10-2 mol-1min-1
b. 60×10-6 mol-1min-1
c. 36×10-1mol-1min-1
d. 36×10-4 mol-1min-1
9. For the reaction, 2N2O5 → 4NO2 + O2, rate and rate constant are 1.02 × 10-4 and 3.4 × 10-5 sec-1 respectively then concentration of N2O5 at that time will be
a. 3
b. 1.732
c. 1.02 × 10-4
d. 3.4 × 105
10. If the rate of the reaction is equal to the rate constant, the order of the reaction is
a. 0
b. 3
c. 2
d. 1
11. Which statement is true for the general rate law: Rate = k [A]m [B]n?
a. It can be written from the stoichiometry of the overall reaction.
b. The exponents in the rate law must be positive integers.
c. The overall order of the reaction is equal to ‘m’ times ‘n’.
d. The values for the exponents must be determined by experiment.
12. For a reaction that follows the general rate law, Rate = k [A] [B]2, what will happen to the rate of reaction if the concentration of A is increased by a factor of 3.00? The rate will
a. Decrease by a factor of 1/6.00.
b. Increase by a factor of 6.00.
c. Increase by a factor of 3.00.
d. Decrease by a factor of 1/3.00.
13. For a reaction that follows the general rate law, Rate = k [A] [B]2, what will happen to the rate of reaction if the concentration of B is increased by a factor of 2.00? The rate will:
a. Increase by a factor of 2.00.
b. Increase by a factor of 4.00.
c. Decrease by a factor of 1/2.00.
d. Decrease by a factor of 1/4.00.
14. The unit of rate constant ‘K’ for a zero order reaction:
a. mol.dm–3. sec–1
b. sec–1
c. mol–1.dm3. sec
d. mol.dm–3. sec
15. The rate equation for a reaction is Rate = K[A], what are the units of K:
a. mol.dm–3.s–1
b. sec–1
c. mol–1. dm3.s–1
d. mol.dm–3
16. The unit of rate constant “K” is mol–1.dm3.sec–1 for a chemical reaction the order of reaction is:
a. 2
b. 0
c. 3
d. 1
17. The rate constant of a first order reaction is 3 × 10-6 per second. If the initial concentration is 0.10 M, the initial rate of reaction is
a. 3 × 10-8 Ms-1
b. 3 × 10-5 Ms-1
c. 3 × 10-7 Ms-1
d. 3 × 10-6 Ms-1
18. The units of 3rd order rate constant are usually expressed as
a. mole-2 dm6 s-1
b. mole-1 dm3 s-1
c. mole-2 dm-6 s-1
d. mole-1 dm-3 s-1
19. The rate of a chemical reaction tells us about
a. how slow or fast the reaction is taking place
b. the reactants taking part in the reaction
c. type of catalyst used
d. the products formed in the reaction
20. The average rate and instantaneous rate of a reaction are equal
a. at the end
b. at the start
c. when two rates have a time interval equal to
d. in the middle
21. Spontaneous reactions are
a. Fast
b. Moderate
c. Not natural
d. Slow
22. Which of the following factors affect rate of reaction?
a. Catalyst
b. Concentration
c. surface area
d. all of the above
23. In which of the following techniques, rate of reaction is directly related with reaction of 2-butanol oxidation.
a. Polarimetry
b. Spectrometry
c. Refractrometry
d. Conductometry
24. If the temperature of the reaction is increased from 0oC to 50oC how many times rate will increase?
a. 10 times
b. 5 times
c. 32 times
d. 2 times
25. One of the following does not affect the rate of reaction:
a. Light
b. Conc. of reactants
c. Surface area of products
d. Temperature