Concentration data is commonly monitored during a reaction to determine the order with respect to a reactant. Consider the types of observations listed, and determine which order is likely for that reactant. Assume all other factors are held constant. The reaction rate increases in direct proportion to the concentration of the reactant in solution. a. The reaction rate is constant regardless of the amount of reactant in solution.
b. An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially.

The reaction rate increases in direct proportion to the concentration of the reactant in solution - second order reaction

The reaction rate is constant regardless of the amount of reactant in solution - zero order reaction

An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially - first order reaction

Explanation:

In a second order reaction, the rate of reaction is directly proportional to the concentration of reactants. This implies that, reaction rate varies as the concentration of the reactant in solution varies.

For a zero order reaction, the rate of reaction is independent of the concentration of the reactants in solution. This means that reaction rate is constant regardless of the amount of reactant in solution.

For a first order reaction, the rate of reaction varies exponentially as the concentration of reactants. Hence, an increase or decrease in the concentration of the reactant in solution causes the reaction rate to increase or decrease exponentially.