Reaction Rate and Order:

The rate of a chemical reaction refers to how quickly reactants are consumed and products are formed. It is determined by the rate equation, which shows how the concentration of reactants influences the rate of the reaction. The order of a reaction refers to the power to which the concentration of a reactant is raised in the rate equation.

Uniform Rate throughout the Reaction:

When a reaction proceeds with a uniform rate throughout, it means that the rate of the reaction remains constant over time. This implies that the concentration of the reactants does not affect the reaction rate. In other words, the reaction is not dependent on the concentration of the reactants.

Zero Order Reaction:

When the reaction rate is independent of the concentration of the reactants, it is referred to as a zero order reaction. In this case, the rate equation is expressed as:

Rate = k

where k is the rate constant. The rate of the reaction is solely determined by the value of the rate constant, and it does not change with changes in reactant concentrations.

Explanation:

In the given question, if the reaction proceeds with a uniform rate throughout, it indicates that the rate of the reaction does not depend on the concentration of the reactants. This is a characteristic of a zero order reaction.

The rate equation for a zero order reaction is Rate = k, where k is the rate constant. It means that the reaction proceeds at a constant rate, regardless of the initial concentrations of the reactants. The rate constant determines the speed of the reaction, and it remains constant throughout the reaction.

Therefore, the correct answer is option 'D' - Zero order.