Question

A pseudo-first order approximation

A) Requires using a large excess of one of the reagents in the reaction
B) Is a way to simplify the study of the rates of a second order reaction
C) Gives a straight line when ln[R] is plotted versus time and the resulting positive slope is equal to the rate constant
D) A and B
E) A and C
F) All of the above

Answer 1

F) All of the above

Step-by-step explanation:

The order of a reaction is determined by its kinetics. So, for a reaction

A + B → C

the rate of the C formation is:

`rC = k[C]^n`

Where n is the kinetics' coefficient and determinates the order. If n = 1, the reaction is first order, if n = 2, its second order.

Reactions of the first order are easy to study, so, it's convenient, sometimes, to treat a second-order reaction as a first-order one (pseudo-first order). For this one of the reactants must be in large excess, so the reaction will be completed. For the first-order reaction equation:

rC = k[C]

ln(rC) = ln(k) + ln [C]

Which is a line equation, so the letter C is also correct.