Question

Consider the following statements:
1. Rate of a process is directly proportional to its free energy change.
2. The order of an elementary reaction step can be determined by examining the stoichiometry.
3. The first-order reaction describes the exponential time course
Of these statements:
A. 1, 2, and 3 are correct
B. 1 and 2 are correct
C. 2 and 3 are correct
D. 1 and 3 are correct

Answer 1

Hint: Rate of reaction is defined as the decrease in the concentration of a reactant or an increase in the concentration of reactants concerning time and rate of reaction gets affected by the concentration of reactants and also the physical state of catalysts.

Complete step by step answer:
Free energy or Gibbs free energy depends on the difference of the energy of the reactant and the product but is unaffected by the mechanism of the reaction and rate of a reaction. Hence the statement 1 that says the rate of a process is directly proportional to its free energy change is wrong. Instead, the rate of reaction is also known as activation energy. For the case of an elementary reaction, each reaction step has reaction steps equal to stoichiometric coefficients and hence the order of an elementary reaction can be determined by examining the stoichiometry of a reaction. Hence, statement 2 is correct. For the case of the first-order reaction, the rate of reaction is dependent linearly on the concentration of only one reactant, and hence the statement 3 that says the first-order reaction describes the exponential time course is correct.

Since the statement 2 and 3 are correct, we can say the correct answer is option C.

Note: Order of reaction can have any value be it positive, negative, or fractional and even zero. For the case of the Zero order reaction, the rate of a reaction is not affected by the concentration of reactants. In the case of positive order of reaction, the rate of reaction is directly proportional to the concentration of reactants, and in the case of negative order of reaction, the rate of reaction is inversely proportional to the concentration of reactants.