First Order Reactions-Multiple Choice Questions Quiz

Interactive MCQs on “First Order Reactions”:

Solve the following 10 questions. Only one option is correct. Click on the “Submit” button when done. Click on the “embed” button to use this quiz on your website. Click on “WhatsApp” to share this quiz.

Question 1: In a first-order reaction, the rate of reaction is directly proportional to the:

(a) Concentration of the reactants
(b) Square of the concentration of the reactants
(c) Cube of the concentration of the reactants
(d) Inverse of the concentration of the reactants

Question 2: What is the half-life of a first-order reaction?

(a) It remains constant
(b) It doubles with each reaction
(c) It decreases with time
(d) It increases with time

Question 3: The integrated rate equation for a first-order reaction is typically expressed as:

(a) ln[A] = -kt + ln[A]0
(b) [A] = -kt + [A]0
(c) ln[A] = kt + ln[A]0
(d) [A] = kt + [A]0

Question 4: The unit of the rate constant (k) for a first-order reaction is:

(a) mol/L/s
(b) L/mol/s
(c) s/mol
(d) 1/s

Question 5: Which statement accurately describes the relationship between the rate constant (k) and temperature in a first-order reaction?

(a) k decreases with temperature
(b) k increases with temperature
(c) k remains constant with temperature
(d) k is inversely proportional to temperature

Question 6: If the concentration of a reactant is halved after 20 minutes in a first-order reaction, what is the approximate value of the rate constant (k)?

(a) 0.0345 min⁻¹
(b) 0.0173 min⁻¹
(c) 0.693 min⁻¹
(d) 1.386 min⁻¹

Question 7: What is the graphical representation of a first-order reaction when plotting ln[A] against time (t)?

(a) Linear with a positive slope
(b) Linear with a negative slope
(c) Exponential increase
(d) Parabolic curve

Question 8: The rate constant (k) of a first-order reaction can be determined from the slope of the graph of:

(a) [A] vs. t
(b) ln[A] vs. t
(c) 1/[A] vs. t
(d) √[A] vs. t

Question 9: Which statement describes the behavior of the concentration of a reactant in a first-order reaction over time?

(a) It remains constant
(b) It increases linearly
(c) It decreases linearly
(d) It decreases exponentially

Question 10: If a first-order reaction has a rate constant of 0.025 min⁻¹, what is the half-life of the reaction?

(a) 10.98 min
(b) 27.72 min
(c) 13.86 min
(d) 6.93 min