Rate of Reaction Questions & Answers on Organic Chemistry

1. The rate of the reaction is equal to the product of three factors listed below except ______

a) Collision frequency
b) Energy factor
c) Orientation factor
d) pH factor

Answer: d

Explanation: The reaction rate is given by the product of collision frequency (deals with concentration, pressure, and arrangement), energy factor (deals with distribution of kinetic energy), and orientation factor (probability factor).

2. Temperature and pressure are the only factors which affect the reaction rate.

a) True
b) False

Answer: b

Explanation: The rate of reaction is affected by three factors temperature, pressure, and concentration. All the three varies directly with the rate of the reaction.

3. The frequency of molecular collision increases if _______

a) The concentration of product increases
b) The concentration of product decreases
c) The concentration of reactant increases
d) The concentration of reactant decreases

Answer: c

Explanation: The frequency of molecular collision increases varies directly with the concentration of the reactant.

4. Identify the true statement regarding catalyst.

a) Always decreases the rate of the reaction
b) Always increases the activation energy of the reaction
c) Actually participates in the reaction
d) Changes the equilibrium concentration of the product

Answer: c

Explanation: A catalyst is a substance which when added, only alters the reaction rate temporarily and does not have a permanent effect on them and hence, only the option “Always increases the activation energy of the reaction” gives a correct info from the given choices.

5. From the choices given below, identify the activation energy of a reaction whose rate constant increases by 100 when the temperature changes from 300K to 360K.

a) 53
b) 69
c) 35
d) 42

Answer: b

Explanation: By substituting the appropriate values in the formula: (R.T1.T2)/(T1-T2)*ln(k1/k2)
we can find the value of activation energy(Ea).

6. Identify the unit of “k” in moles/L for the rate law: k[A][B]pow2.

a) L/mol/s
b) L(pow2)/mol/s
c) L(pow2)* s(pow2)/mol(pow2)
d) s

Answer: d

Explanation: Rate = k[A][B](pow2) and hence k=rate/{[A][B](pow2)}.

7. Which among the following catalyst increases the rate of the reaction?

a) Calcium carbonate
b) Calcium chloride
c) Calcium hydroxide
d) Calcium sulphate

Answer: a

Explanation: Calcium carbonate has large surface area and hence it increases the reaction rate.

8. Which is not a type of catalyst?

a) Positive catalyst
b) Negative catalyst
c) Autocatalyst
d) Homogeneous catalysis

Answer: d

Explanation: Homogeneous catalysis is a phenomenon in which the catalyst takes part in the reaction and it is not a type of catalyst.

9. What is the speed of a chemical reaction?

a) Is independent of the contact surface
b) Is constant no matter what the temperature is
c) Varies inversely with the absolute temperature
d) Is extremely rapid between the ions in aqueous solution

Answer: d

Explanation: The speed of a chemical reaction is extremely rapid between the ions in aqueous solution because there are no bonds that need to be broken.

10. The overall order for the reaction 2A+ B—> 2C with rate equation rate=k[A]^2[B] is?

a) 0
b) 1
c) 2
d) 3

Answer: d

Explanation: The order of A in this reaction is 2 and the overall reaction is a third order reaction.

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