Question

At 325 ˚C,1,3 -butadiene dimerizes according to the equation: 2C₄H₆( g)→C₈H₁₂( g). It is found that the partial

pressure, P, of the reactant obeys the law:
1P=kt+1P0. Order of the reaction is
(a) 1
(b) 0.50.5
(c) 2
(d) 1.51.5

Answer 1

Based on the rate law provided, 1,3-butadiene undergoes a second-order dimerization reaction since it adheres to an integrated rate law that is typical for second-order kinetics. The correct answer is option (c) 2.

Step-by-step explanation:

• The partial pressure, P, of the reactant 1,3-butadiene dimerizing to form C8H12 follows the rate law 1/P = kt + 1/P0, where k is the rate constant and P0 is the initial partial pressure.
• This expression suggests a second-order reaction because the rate law formula that corresponds to a second-order reaction, in terms of concentration, is 1/[A] = kt + 1/[A]0.
• The integrated rate law for a second-order reaction in terms of pressure behaves similarly to the concentration-based rate law, which indicates that the reaction is of second order.
• In the given problem statement, k represents the rate constant, t the time, and P0 the initial partial pressure. Therefore, based on the given rate law, the correct answer for the order of the reaction is (c) 2.
• An example of a similar second-order reaction is the dimerization of butadiene gas (C4H6) to yield C8H12 gas with a known rate constant under specified conditions.