Question

Please show work and explain:

The reaction A + B → C is studied similarly to our study of phenolphthalein fading kinetics.

The corresponding rate law is Rate = k[A]m[B]m

In this particular experiment, the concentration of A is sufficiently high that the pseudo-order rate law: Rate = k1[B]n can be written, where k1 = k[A]m.

If the study establishes that the reaction is first order in B (n = 1) and that the pseudo rate constant k1 has the following values at varying concentrations of B, what is the order of the reaction in reactant A (what is the value of m)?

k1	[B]
0.0034	0.200 M
0.0020	0.100 M
0.0010	0.050 M

Options:

A.

0

B.

1

C. 2

D.

3

Answer 1

Concepts and reason

oThe rate constant of the reaction at a given temperature is defined as the rate of the reaction when the molar concentration of each of the reactants is unity.

oThe rate of the reaction depends on the reactant concentration.

oThe rate of a reaction is proportional to some power of the molar concentration of each of the reactants.

oThe rate constant can be determined by using the rate law.

Fundamentals

The rate of the reaction in terms of concentration of the reactants that determine the rate of the reaction is called the rate law or rate equation.

Rate law for a general reaction is

Pseudo order reaction: The reaction in which the reactant concentration remains constant; its concentration is very high, so it does not involve in the rate of the reaction.

Consider the given reaction,

Reaction is first order with respect to reactant B.

The pseudo order rate is

The reaction is first order with respect to [B] with rate constant .

Using the given table, concentration of is decreasing the rate also decreasing

Therefore, order of the reaction with respect to is 1.

Value of m is 1.

Ans: